Configurable counterbalance mechanism

ABSTRACT

Implementations relate to a configurable counterbalance mechanism. In some implementations, a counterbalance apparatus includes a spring, a tension element coupled between the spring and a mechanical ground, a base element coupled to a load, and a configurable arm rotatably coupled to the base element. A first pulley and a second pulley are rotatably coupled to the configurable arm, the second pulley orbitable about the first axis, and the tension element is at least partially wrapped around the first pulley and the second pulley. The configurable arm is rotatably configurable at either a first orientation or a second orientation, where the first orientation is associated with a center of gravity of the load located on a first side of the counterbalance apparatus and the second orientation is associated with the center of gravity of the load located on a second side of the counterbalance apparatus opposite to the first side.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 63/195,407, filed Jun. 1, 2021 and titled “ConfigurableCounterbalance Mechanism,” the entire contents of which are herebyincorporated by reference.

BACKGROUND

Load positioning systems can be used in a variety of applications. Inone example, a control input device can include a grip held by a user,where the grip is connected to a mechanical linkage such as a mechanicalarm. The grip can be moved by the user in one or more degrees of freedomprovided by the mechanical arm to provide input to a system, such thatthe user contact on the grip acts as a load on the mechanical arm. Insome examples, the grip is included in a control input device that canbe manipulated by a user to control functions of a manipulator device,including movement and other operations of the manipulator device. Forexample, forces can be applied to the mechanical arm by motors toprovide force feedback to the control input device and/or to positionthe grip in a particular workspace. For example, input control devicescan be used in teleoperated systems such as teleoperated surgicaldevices that allow the user to control various types of medicalinstruments at a surgical site to perform surgical procedures. Otherteleoperated systems can also make use of control input devices to allowa user to control one or more manipulator devices at a worksite. Inother examples, load positioning systems can be provided at themanipulator device of a teleoperated system, e.g., at mechanicallinkages of the manipulator device used to move and hold various endeffectors such as surgical instruments or other tools. Further, loadpositioning systems can be used in other types of control input devicesand other devices that are not part of a teleoperated system.

In some implementations of load positioning systems, a counterbalanceforce is applied to the mechanical arm by a counterbalance mechanism tocompensate for the effects of gravity on the mechanical arm. Forexample, the counterbalance mechanism can include springs that providethe counterbalance force. In some examples, the use of a counterbalancemechanism allows gravity compensation when motors are not powered, andallows forces of lower magnitude to be output by the motors to themechanical arm since the motors need not provide as much counterbalanceforces themselves to compensate for gravity. In one example, thecounterbalance mechanism may provide a reduction in the speed and/ormagnitude of motion of the arm falling through space, e.g., when theuser removes his or her grip from an input control device connected tothe arm.

In some systems, a user control system can include a left input controldevice and a right input control device that are positioned to bemanipulated by a user's left hand and right hand, respectively. The leftinput control device may have a different configuration than the rightinput control device to accommodate the associated hand. For example,the counterbalance mechanism of a control device has a configurationbased on a center of gravity of the control input device that themechanism is balancing. This configuration is changed based on whetherthe control input device is for left-handed use or right-handed use. Forexample, the center of gravity of the counterbalanced load can be onopposite sides of the counterbalance mechanism for the left-handed andright-handed configurations.

One previous method to reconfigure the counterbalance mechanism for leftor right handed use of a control input device includes moving a lowerpulley (including a rotating pulley and a grounded cylinder) of thecounterbalance mechanism with reference to the other pulleys of thecounterbalance mechanism, thus providing left handed and right handedconfigurations for the device. For example, in the da Vinci Xi® surgicalsystem's surgeon console, commercialized by Intuitive Surgical, Inc.,the lower pulley is moved to either side of a vertical equilibrium axisof the load depending on the selected configuration. However, thiscounterbalance mechanism is limited in its reconfiguring ability to theavailable space in which the lower pulley may be moved. For example,this mechanism may not be suitable for implementations in which thecounterbalanced load has a center of gravity that is located a largedistance away from the vertical axis that intersects the axis ofrotation of the load (the vertical equilibrium position of the load). Insome examples, such a center of gravity location can be caused by a loadhaving a heavy mass, or having extended portions or uncompacted form.When using the previous counterbalance mechanism for such a load, movingthe lower pulley by a larger amount would be required in response to thecenter of gravity being changed. However, such larger lower pulleymovement may not be possible due to constraints of a housing orpackaging of the mechanical arm. Such counterbalance mechanisms do notenable fast and easy changes to its components to accommodate such achange of location of a load that has a center of gravity farther fromthe vertical axis of the counterbalance mechanism.

Furthermore, the cable of this previous counterbalance mechanism remainsin place when the lower pulley is moved in position. Thus, the tensionin the cable, as indicated by the stretch of the counterbalance springwhen the load is in a home position, is higher in one configuration thanin the other configuration. This counterbalance mechanism thereforeprovides different gravity counterbalance performance in oneconfiguration than in the other, causing inconsistency in performance.In some cases, counterbalance mechanisms may be specifically producedfor left-handed or right-handed use, causing inefficiency in productionand maintenance of control input devices.

In addition, existing counterbalance mechanisms may producecounterbalance forces that inaccurately counter gravity forces on a loadat all rotational angles of the load and also may introduce undesiredfriction in the motion of the counterbalanced load. For example, a cablethat wraps around the pulleys of a counterbalance mechanism may wraparound one pulley or element at one level or height, and wrap around adifferent pulley or element at a different level or height. This cancause inaccuracies in the produced counterbalance force since thecounterbalance mechanism is typically designed without taking account ofsuch a difference in levels. In addition, the difference in levels cancause the cable to skew out of the center of the groove located in itsouter circumference and rub against sides of the groove, causingfriction in the movement of the cable and in the rotation of the loadabout an axis.

SUMMARY

Implementations of the present application relate to a configurablecounterbalance mechanism. In some implementations, a counterbalanceapparatus includes a spring and a tension element including a first endcoupled to the spring and a second end coupled to a mechanical ground.The apparatus includes a base element coupled to a load and aconfigurable arm that includes a first portion and a second portion, thefirst portion being rotatably coupled to the base element, and theconfigurable arm being rotatable about a first axis. A first pulley isrotatably coupled to the first portion and rotatable about the firstaxis, and a second pulley is rotatably coupled to the second portion andis rotatable about a second axis and orbitable about the first axis. Thetension element is at least partially wrapped around the first pulleyand the second pulley, and the configurable arm is rotatablyconfigurable about the first axis at one of a first orientation and asecond orientation. The first orientation is associated with a center ofgravity of the load located on a first side of the counterbalanceapparatus, and the second orientation is associated with the center ofgravity located on a second side of the counterbalance apparatus that isopposite to the first side.

Various implementations and examples of the counterbalance apparatus aredescribed. For example, in some implementations, a third axis intersectsthe first axis, the second axis, and a center of gravity of the load. Insome implementations, the configurable arm includes a length defined bythe first portion and the second portion, and the length aligned with athird axis that intersects the first axis, the second axis, and thecenter of gravity of the load. In some implementations, thecounterbalance apparatus further includes a first stop member associatedwith the first orientation of the configurable arm and a second stopmember associated with the second orientation of the configurable arm,the first stop member being located in a path of clockwise rotation ofthe configurable arm about the first axis, and the second stop memberbeing located in a path of counterclockwise rotation of the configurablearm about the first axis. In some implementations, the first portion ofthe configurable arm is rotatably coupled to the base element by ashaft. In some implementations, the base element is a joint gear that isrigidly coupled to a rotatable shaft having a length and an axis ofrotation, the configurable arm is rotatably coupled to the rotatableshaft, and the second pulley is coupled to the second portion of theconfigurable arm such that the second axis of the second pulley is at alocation offset from the axis of rotation of the rotatable shaft.

In some implementations, the base element includes a first slot and asecond slot, and the configurable arm engages with the first slot at thefirst orientation and engages with the second slot at the secondorientation of the configurable arm. In some implementations, theconfigurable arm includes a plug portion that includes first taperedsides engageable with second tapered sides of the first slot and thesecond slot of the base element. In some implementations, the secondportion of the configurable arm includes a first aperture, the firstaperture includes a threaded portion and a clearance portion, and a boltextends through the first pulley, through the first aperture, and into asecond aperture of the base element. In some implementations, the firstorientation of the configurable arm counterbalances the center ofgravity of the load located on the first side of the counterbalanceapparatus, and the second orientation of the configurable armcounterbalances the center of gravity of the load located on the secondside of the counterbalance apparatus. In some implementations, thetension element is a cable.

In some implementations, the counterbalance apparatus further includes athird pulley rotatably coupled to the mechanical ground, and the tensionelement is wrapped at least partially around the third pulley prior tobeing wrapped around the second pulley in a path of the first end to thesecond end of the tension element. In some implementations, thecounterbalance apparatus further includes a fourth pulley rotatablycoupled to the mechanical ground, and the tension element is wrapped atleast partially around the fourth pulley prior to being wrapped aroundthe third pulley in the path of the first end to the second end of thetension element.

In some implementations, the counterbalance apparatus further includes acurved element coupled to the mechanical ground and having a curvedsurface, and a third pulley rotatably coupled to the curved element androtatable about a third axis of rotation that is nonparallel to thefirst axis and the second axis; wherein, in a path from a first end to asecond end of the tension element, the tension element is wrapped atleast partially around the third pulley prior to being wrapped aroundthe second pulley, and the tension element is at least partially wrappedaround the curved element prior to being coupled to the mechanicalground at the second end of the tension element; and along the path fromthe first end to the second end of the tension element, the tensionelement exits contact with the third pulley and enters contact with thecurved surface of the curved element at points located within a planethat includes the first pulley and the second pulley. In some examples,the plane is orthogonal to the first axis and the second axis, and thethird axis of rotation is at a non-orthogonal angle with reference tothe plane. In some examples, the curved element is rigidly coupled tothe mechanical ground, is centered on the third axis, and is locatedbetween the third pulley and the mechanical ground, the curved surfaceof the curved element having a radius equal to a radius of the thirdpulley. In some implementations, the counterbalance apparatus furtherincludes a fourth pulley rotatably coupled to the mechanical ground androtatable about a fourth axis, the tension element is wrapped at leastpartially around the fourth pulley prior to being wrapped around thethird pulley in the path from the first end to the second end of thetension element, and the fourth axis is nonparallel to the first axis,the second axis, and the third axis.

In some implementations, the first portion of the configurable armincludes an edge and a slot in the edge, the slot configured to receivea separation tool to slide or pry the configurable arm away from thebase element. In some implementations, the load includes a mechanicalmember rigidly coupled to the base element, the mechanical member beingrotatable about the first axis. In some implementations, thecounterbalance apparatus is included in a component of a teleoperatedsurgical system.

In some implementations a method to configure a counterbalance mechanismincludes disengaging an attachment mechanism that secures a configurablearm of the counterbalance mechanism to a base element of thecounterbalance mechanism at a first orientation of the configurable armabout an axis, the base element being rigidly coupled to a load of thecounterbalance mechanism. The counterbalance mechanism includes a firstpulley rotatably coupled to the configurable arm, a second pulleyrotatably coupled to the configurable arm, a spring, and a tensionelement coupled to the spring and wrapped at least partially around thefirst pulley and the second pulley. The method includes moving theconfigurable arm away from the base element and along a shaft in adirection along the axis and perpendicular to a plane of rotation of theconfigurable arm, rotating the configurable arm about the axis to arotated orientation, moving the configurable arm at the rotatedorientation toward the base element along the shaft to engage theconfigurable arm with the base element, and engaging the attachmentmechanism to secure attachment of the configurable arm with the baseelement at a second orientation of the arm about the axis. When theconfigurable arm at the first orientation, the counterbalance mechanismcounterbalances a load having a center of gravity located on a firstside of the counterbalance mechanism, and when the configurable arm isat the second orientation, the counterbalance mechanism counterbalancesthe load having the center of gravity located on a second side of thecounterbalance mechanism opposite to the first side.

In various implementations of the method, a third axis intersects afirst axis of rotation of the first pulley, a second axis of rotation ofthe second pulley, and the center of gravity of the load. In someimplementations, rotating the configurable arm about the axis to therotated orientation includes rotating the configurable arm to a stoppedorientation against a stop member provided in a range of motion of theconfigurable arm, the stopped orientation aligning or approximatelyaligning the configurable arm to the second orientation. In someimplementations, a first slot and a second slot are provided in the baseelement, a tapered member is provided on the configurable arm, the firstslot provided at the first orientation, and the second slot provided atthe second orientation; moving the configurable arm away from baseelement along the shaft causes the tapered member of the configurablearm to disengage from the first slot of the base element; and the methodincludes providing a precise alignment of the configurable arm to thesecond orientation by moving the configurable arm toward the baseelement along the shaft to cause the tapered member of the configurablearm to engage in the second slot of the base element at the secondorientation. In some implementations, the load includes a mechanicallinkage coupled to the base element, and the counterbalance mechanism isincluded in a component of a teleoperated surgical system.

In some implementations, a counterbalance apparatus includes a spring, atension element including a first end coupled to the spring and a secondend coupled to a mechanical ground, a first pulley rotatably coupled toa rotatable member of a load and rotatable about a first axis, a secondpulley rotatably coupled to the rotatable member of the load androtatable about a second axis parallel to and offset from the firstaxis, a curved element coupled to the mechanical ground and including acurved surface, and a third pulley rotatably coupled to the curvedelement and rotatable about a third axis nonparallel to the first axisand the second axis. The tension element is at least partially wrappedaround the first pulley and the second pulley, and is at least partiallywrapped around the third pulley prior to being wrapped around the firstpulley in a path from the first end to the second end of the tensionelement. In the path from the first end to the second end of the tensionelement, the tension element is at least partially wrapped around thecurved element prior to being coupled to the mechanical ground at thesecond end of the tension element. Along the path from the first end tothe second end of the tension element, the tension element exits contactwith the third pulley and enters contact with the curved element atpoints located within a plane that includes the first pulley and thesecond pulley.

Various implementations and examples of the apparatus are described. Insome implementations, the third axis of rotation extends at anon-orthogonal angle with reference to the plane, and the plane isorthogonal to the first axis and the second axis. In someimplementations, the first axis and the second axis are arranged alongan axis that intersects a center of gravity of the load of thecounterbalance apparatus. In some implementations, the curved element isa cylindrical element that is rigidly coupled to the mechanical ground,centered on the third axis, and positioned between the third pulley andthe mechanical ground, the curved surface of the curved element having aradius equal to a radius of the third pulley. In some implementations,the counterbalance apparatus further includes a fourth pulley rotatablycoupled to the mechanical ground and rotatable about a fourth axis,wherein the tension element is wrapped at least partially around thefourth pulley prior to being wrapped around the third pulley in the pathfrom the first end to the second end of the tension element, and thefourth axis is nonparallel to the first axis, the second axis, and thethird axis. In some implementations, the second pulley is coupled to abase element that is rotatable about the first axis, the second pulleyis orbitable about the first axis, the base element is rigidly coupledto a load, and the load includes at least a portion of a mechanical arm.In some implementations, the counterbalance apparatus further includes aconfigurable arm having first and second portions, the configurable armhas a first configuration orientation and a second configurationorientation, the configurable arm is rotatably coupled to the baseelement at the first portion of the configurable arm and is rotatableabout the first axis to the first configuration orientation and to thesecond configuration orientation, and the configurable arm has a lengthaligned with an axis intersecting a center of gravity of a load coupledto the base element.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an example counterbalancemechanism that can include one or more features of the presentdisclosure, according to some implementations;

FIG. 2 is a diagrammatic illustration of an example implementation of ateleoperated surgical system which can be used with one or more featuresdisclosed herein, according to some implementations;

FIG. 3 is a front elevational view of an example user control system asshown in FIG. 2 , according to some implementations; and

FIG. 4 is a perspective view of a portion of a control input armassembly that includes one or more counterbalance features describedherein, according to some implementations;

FIG. 5 is a perspective view of a portion of the interior of a link ofthe control input arm assembly of FIG. 4 , according to someimplementations;

FIG. 6 is a perspective view of the counterbalance mechanism withoutother portions of first link shown in FIG. 5 , according to someimplementations;

FIGS. 7A and 7B are front views of the counterbalance mechanism of FIG.6 in first and second configurations, respectively, according to someimplementations;

FIG. 8 is a front view of an example implementation of a joint gear ofthe counterbalance mechanism of FIGS. 5-7B, according to someimplementations;

FIGS. 9A, 9B, and 9C are front, side cross-sectional, and perspectiveviews, respectively, of an example configurable arm that can be used inthe counterbalance mechanism of FIGS. 5-7B, according to someimplementations;

FIG. 10 is a side elevational view of an example bolt that can be usedto secure the configuration arm to the joint gear in the counterbalancemechanism of FIGS. 5-7B, according to some implementations;

FIGS. 11A, 11B, 11C, and 11D are perspective views of a portion of thecounterbalance mechanism of FIGS. 5-7B in which a configurable arm is indifferent orientations and positions, according to some implementations;

FIG. 12 is a perspective view of the portion of control input armassembly of FIG. 4 in which the arm assembly has been reconfigured to aright-handed configuration, according to some implementations;

FIG. 13 is a front view of an example counterbalance mechanism showingplanar counterbalance features, according to some implementations;

FIG. 14 is a side elevational view of the tension element, thirdcounterbalance pulley, and curved element of the counterbalancemechanism of FIG. 13 , according to some implementations;

FIG. 15 is a flow diagram illustrating an example method to configure acounterbalance mechanism, according to some implementations;

FIG. 16 is a perspective view of an example control input device thatcan be used in the arm assembly of FIG. 4 , according to someimplementations; and

FIG. 17 is a block diagram of an example control system which can beused in one or more implementations described herein.

DETAILED DESCRIPTION

Implementations described herein relate to a configurable counterbalancemechanism. In some implementations of a counterbalance mechanism, afirst end of a tension element (e.g., a cable) is coupled to a springand a second end is coupled to a mechanical ground. A base element iscoupled to a load and a configurable arm is rotatably coupled to thebase element. A first pulley is rotatably coupled to a first portion ofthe configurable arm and is rotatable about a first axis. A secondpulley is rotatably coupled to a second portion of the configurable armand is rotatable about a second axis and orbitable about the first axis.The tension element is at least partially wrapped around the firstpulley and the second pulley. The configurable arm is rotatablyconfigurable about the first axis at one of a first orientation and asecond orientation. The first orientation is associated with a center ofgravity of the load located on a first side of the counterbalancemechanism, and the second orientation is associated with the center ofgravity of the load located on a second side of the counterbalancemechanism opposite to the first side. Thus, the load center of gravitycan be located to either side of the counterbalance mechanism and thecounterbalance mechanism is configured to counterbalance the loadpositioned at the selected side.

Various features of the counterbalance mechanism are disclosed. Forexample, the counterbalance mechanism can include a third pulleyrotatably coupled to the mechanical ground, the tension element beingwrapped at least partially around the third pulley. In someimplementations, the base element can be a joint gear. In someimplementations, the base element can include a first slot and a secondslot, where the configurable arm engages with the first slot at thefirst orientation and engages with the second slot at the secondorientation. For example, the configurable arm can include a plugportion that includes tapered sides that are engageable with taperedsides of the slots of the base element, such that the tapered sidesprecisely guide the configurable arm into a slot.

A stop member can be associated with each configuration orientation,being located in the path of rotation of the configurable arm andstopping the rotation of the configurable arm such that it is aligned orapproximately aligned with a targeted configuration orientation. Thecounterbalance mechanism can include a grounded guide pulley that guidesthe tension element to the spring.

In some described implementations, a counterbalance mechanism includesactive portions of a tension element that are located within a singleplane. For example, the third pulley can be rotatably coupled to acurved element that is coupled to ground. The third pulley can berotatable about a third pulley axis that is angled such that, in a pathfrom a first end to a second end of the tension element, the tensionelement exits contact with the third pulley and enters contact with thecurved surface of the curved element at points located within a singleplane that includes the first pulley and the second pulley.

Described configuration features allow a counterbalance mechanism to bequickly and easily reconfigured based on a location of a center ofgravity of the counterbalanced load. For example, in some systems aleft- or right-handed counterbalanced control input device may bechanged to the other handedness in which the center of gravity of thecontrol input device is flipped to the opposite side of thecounterbalance mechanism. A counterbalance arm of the counterbalancemechanism can be quickly rotated from one configuration orientation toanother configuration orientation as needed to balance the load on aparticular side of the counterbalance mechanism. Features such as aconfiguration slot that receives a plug portion of the configurable arm,and tapered sides of both slot and arm, assist and guide thedisengagement, rotation, and engagement of the configurable arm to a newconfiguration orientation. Stop members in the range of rotation of theconfigurable arm prevent rotation of the configurable arm past a targetconfiguration orientation and assist guiding the arm to a neworientation.

These features provide simple and quick reconfiguration for acounterbalance mechanism that can be used to balance a load that has acenter of gravity that can change its location (e.g., position ororientation) with respect to the counterbalance mechanism. For example,a load that is a control input device can be rotated 180 degrees from aleft-handed configuration to a right-handed configuration, or viceversa, which can change the center of gravity of this load. Such achange in center of gravity can be counterbalanced using thecounterbalance mechanism and reconfiguration procedure described herein.

Furthermore, one or more described configuration features can balance aload's center of gravity that is located far from the vertical axis ofthe counterbalance mechanism without requiring a large volume to changelocations of components of the mechanism. For example, the describedconfigurable arm can be rotated about a joint without requiring largeshifting of components and a large housing or packaging to accommodatesuch shifting. Another advantage of some described implementations isthat the counterbalance mechanism provides the same amount ofcompensation for gravity to a load in all configurations, unlikeprevious designs that move components such as a lower pulley fordifferent configurations, thereby causing different amounts of cabletension and thus different amount of counterbalancing in the differentconfigurations.

Described features allow easier production, distribution, and assemblyof control input device assemblies that are provided in a single type ofconfiguration (e.g., for left hand or for right hand), which can beeasily changed to a desired configuration at an operating site.

In addition, some described implementations can provide activecounterbalance elements in a single plane. This allows a counterbalancemechanism to provide counterbalance forces that more accurately reduceor cancel gravity forces on a load. In addition, this feature canprovide reduced friction between a tension element (such as a cable) andone or more pulleys. In a counterbalance mechanism that includes atension element (e.g., a cable) wrapped around multiple pulleys, one ormore of the pulleys can be angled such that active portions of thetension element are located within a single plane. This allows asinusoidal force to be produced to accurately counterbalance gravityforces on the load at all possible rotational angles of the load. Incontrast, previous implementations placed the active portions of thetension element in multiple planes, such that the counterbalancemechanism did not produce force to fully cancel the gravity force on theload at all rotational angles of the load. Furthermore, the describedfeatures can produce less friction due to the tension element beingwrapped around pulleys within a single plane, thus reducing contact ofthe tension element with the sides of grooves at the circumferences ofthe pulleys. Such described features allow more accuratecounterbalancing of a load and thus greater consistency in usermanipulation of a counterbalanced control input device and intransmission of forces to that device.

The terms “center,” “parallel,” “perpendicular,” “orthogonal,”“aligned,” or particular measurements in degrees, Hertz, or other unitsas used herein need not be exact and can include typical engineeringtolerances. Some implementations herein may relate to various objects interms of their state in three-dimensional space. As used herein, theterm “position” refers to the location of an object or a portion of anobject in a three dimensional space (e.g., three degrees oftranslational freedom along Cartesian X, Y, Z coordinates). As usedherein, the term “orientation” refers to the rotational placement of anobject or a portion of an object (three degrees of rotationalfreedom—e.g., roll, pitch, and yaw around the Cartesian X, Y, and Zaxes). As used herein, the term “pose” refers to the position of anobject or a portion of an object in at least one degree of translationalfreedom and to the orientation of that object or portion of the objectin at least one degree of rotational freedom (up to six total degrees offreedom).

As referred to herein, a mechanically grounded member is constrainedwith respect to possible position and orientation motion in a workingenvironment (e.g., an operating area or room). Such a unit iskinematically coupled to a mechanical ground (e.g., mechanicallyconnected to ground directly or indirectly). As used herein, the term“proximal” refers to an element that is close to (or closer to) amechanical ground and the term “distal” refers to an element that isaway from (or further from) a mechanical ground. The term “torque” asused herein refers to rotational forces and/or refers to a context ofrotational motion, and in various implementations using one or moredescribed features, other types of forces can be used as appropriate inplace of or in addition to torque, e.g., linear forces or other forces,and/or forces in a context of translational motion.

FIG. 1 is a schematic illustration of an example counterbalancemechanism 100 that can include one or more features of the presentdisclosure, according to some implementations. Counterbalance mechanism100 can be used to provide counterbalance forces to a load, e.g., a loadsuch as a rotating member of a mechanical arm, to counter (e.g., cancelor reduce) gravitational forces on the load. The sizes and lengths ofcomponents and distances between components shown in FIG. 1 are notactual dimensions, but rather schematic examples shown for simplicity.Portions shown in dashed lines are representations of components thatare part of a system to which the counterbalance mechanism 100 isconnected.

Counterbalance mechanism 100 is coupled to a load that is counterbalanced against gravity. In this example, the load includes a rotatablemember 130, indicated by dashed lines in FIG. 1 . Rotatable member 130can have a variety of different dimensions, shapes, etc. In someexamples, as shown, rotatable member 130 is coupled by a rotary joint toa grounded member 132, indicated by dashed lines in FIG. 1 . Rotatablemember 130 is rotatable about axis 108 with reference to grounded member132. Grounded member 132 can be a mechanical ground 101 with respect tothe counterbalance mechanism 100. Grounded member 132 can have a varietyof different dimensions, shapes, etc. In some implementations,counterbalance mechanism 100 is provided between rotatable member 130and grounded member 132.

In some implementations, rotatable member 130 and grounded member 132are included in a mechanical arm, e.g., as links in the linkage of amechanical arm. In some implementations, grounded member 132 can becoupled to another member, e.g., another link of the mechanical arm. Insome example implementations, the mechanical arm can be used in a usercontrol system, e.g., the arm can be coupled to a control input devicethat can be manipulated by a user in one or more degrees of freedom. Insome example implementations, the mechanical arm can be used as amanipulator arm in a manipulator device or controlled device operatingat a worksite, and movement of the manipulator arm is controlled by auser that is correspondingly manipulating a control input deviceassociated with the manipulator arm. Some examples of the manipulatorarm are described below. In various other implementations, themechanical arm is used in other applications.

Counterbalance mechanism 100 includes a counterbalance spring 102 andcounterbalance pulleys 103, 104, and 105. A tension element 106 iscoupled to spring 102 and wraps around pulleys 103, 104, and 105.

Spring 102 is coupled to a mechanical ground 101 at a first end of thespring. A second end of spring 102 is coupled to a first end of atension element 106. Spring 102 provides a spring force on tensionelement 106. Spring 102 has a spring constant k. Spring 102 can be usedas a tension spring, as shown, or alternatively as a compression springin which, for example, tension element 106 is coupled to the first endof the spring and passes through the spring, such that a load causes thespring to be compressed.

Tension element 106, and any of the other tension elements described inthe various implementations herein, can be any flexible element that canbe routed to and contacts (e.g., wraps at least partially around) thecomponents of the counterbalance mechanisms described herein. Forexample, one or more tension elements can be a flexible tension element,e.g., a steel tension element. In some implementations, the tensionelements are cables. In some implementations, one or more of the tensionelements can be belt, chains, or other flexible elements. The tensionelements described herein transmit force from one component to another,e.g., from a spring to a load (e.g., via pulley(s)).

Tension element 106 is routed from its first end at spring 102 toward acounterbalance pulley system, where it wraps at least partially againstor around pulley 105, and at least partially around pulleys 103 and 104.After pulley 104, tension element 106 is wrapped at least partiallyaround a curved element (e.g., cylindrical feature) (not shown) that isadjacent to pulley 105 and fixed to the mechanical ground. Tensionelement 106 is anchored at its second end (e.g., at an opposite end tothe first end of tension element 106) to mechanical ground, e.g., at thegrounded curved element adjacent to pulley 105 or otherwise to groundedmember 132. In various implementations, tension element 160 can bewrapped around the curved element by a different amount depending on theimplementation, e.g., depending on the range of motion of rotatingmember 130.

In some examples, from its first end at spring 102, tension element 160wraps partially around pulley 105. In some implementations, pulley 105is rotatably coupled to ground member 132. In some implementations, asdescribed below with reference to FIG. 13 , pulley 105 has the sameradius as counterbalance pulleys 103 and 104 and is angled such that itsaxis of rotation 109 is nonparallel to the axis of rotation 108 of thefirst pulley 103 and axis of rotation 107 of the second pulley 104.

Pulley 103 is rotationally coupled to a member, which in this example isrotatable member 130 (e.g., link) of the mechanical arm, and has axis ofrotation 108 that is coaxial with a joint axis of the rotatable member130 of the mechanical arm. Pulley 104 is rotationally coupled torotatable member 130 and rotates about an axis of rotation 107. Pulley104 is at a location that is offset from axis 108 orbits or swings aboutaxis 108 and pulley 103 with member 130 as member 130 rotates about axis108. Member 130 has a mass m and a center of gravity 110 that is on theopposite side of axis 108 from the pulley 104. The axis of rotation 107is located in a line with center of gravity 110 and axis of rotation108, e.g., an axis 111 intersects the center of gravity 110, axis ofrotation 108, and axis of rotation 107. In some implementations, asdescribed below with respect to FIGS. 4-12 , pulleys 103 and 104 can berotatably coupled to a configurable arm that can be reconfigured basedon a location of the center of gravity 110 with respect to thecounterbalance mechanism, e.g., with respect to vertical axis 113.

After pulley 104 toward its second end, tension element 160 wraps aroundthe curved element adjacent to pulley 105 (e.g., positioned behindpulley 105 in FIG. 1 ). In some implementations, the curved element is acylindrical feature that is fixed to mechanical ground 101, e.g.,rigidly coupled to grounded member 132. The curved element can have thesame radius as pulley 105 and can have a center axis that is coincidentwith (e.g., the same as) rotational axis 109 of pulley 105. In someother implementations, the curved element is not cylindrical and has adifferent shape, or is an element that is a feature or portion ofgrounded member 132. For example, the curved element can be a feature onthe grounded member 132 that that has a curved surface that is a portionof a cylinder that has the same radius as pulley 105. An example of animplementation of the curved element is shown with respect to FIG. 14 .

In some implementations, one or more of the pulleys of thecounterbalance mechanism 100 (or of any of the counterbalance mechanismsdescribed herein) can include grooves and/or flanges on theircircumferential surface to guide and support a tension element thereon,e.g., to cause an engaged tension element to be securely wrapped aroundthe pulley, to stay in place around the pulley, and/or to prevent thetension element from drifting toward an edge of the pulley during pulleyrotation.

In operation, rotatable member 130 can rotate about axis 108. Spring 102provides a counterbalance force on rotatable member 130 via tensionelement 106 in opposition to the force of gravity 112 being exerted onthe rotatable member 130. For example, spring 102 provides a force ontension element 106 which resists the orbiting motion of pulley 104about the axis 108 caused by rotation of rotatable member 130, thusproviding a counterbalance force on rotatable member 130 that opposesgravitational force on the rotatable member. For example, if thecounterbalance mechanism is detached from the rotatable member 130,center of mass 110 would come to a rest at the 6 o′clock position aboutaxis 108. In some example implementations, this application ofcounterbalance forces allows reduced force magnitudes to be output fromactuators (e.g., motors) to move or support the rotatable member 130against gravity as compared to implementations that do not provide suchcounterbalance forces.

As shown in FIG. 1 , an angle θ is denoted between the currentorientation of pulley 104 and an orientation of the pulley 104 thatwould cause the pulleys 103, 104, and 105 to be aligned, e.g., theircenters intersected by a single line. In FIG. 1 , the alignedorientation is along the vertical line 113. This same angle θ existsbetween the center of mass 110 and its stable equilibrium position alongvertical line 113.

Parameters of the counterbalance mechanism 100 include distances betweencomponents of the mechanism 100 and/or rotatable member 130. Oneparameter is a, the planar distance between axis of rotation 108 and theaxis of rotation 107 of pulley 104. Another parameter is b, the planardistance between axis of rotation 108 and the axis of rotation 109 ofpulley 105. The distance between the axis 109 and the axis 107 is d,which is a function of the selected parameters a and b and the angle θ.For example, since pulley 104 rotates with rotatable member 130,distance d varies and is a function of a, b, and angle θ at which therotatable member is currently oriented. The planar distance of center ofmass 110 to axis of rotation 108 is L, which is a parameter of thecounterbalance mechanism as a “lever arm” length of the load of themechanism (rotatable member 130). A different rotatable member 130 (orother load) may have a different mass 110 and/or different lever armlength L. Another design parameter of the counterbalance mechanism 100is k, the spring rate (e.g., spring constant or stiffness) of spring102. The counter balance design parameters k, a, and b can be chosen tobalance the gravity load for the given rotatable member 130 having aparticular mass 110 and lever arm length L.

At any given angle θ, the mass m of the link generates a moment,M_(grav), about the rotary axis 108, as indicated in Equation 1:

M _(grav) =m·g·L·sin(θ)   (1)

where g is the gravitational acceleration.

If the tension element 106 is chosen such that the spring deflection ofspring 102 is equal to the distance a+b when θ is zero, the momentgenerated by the counterbalance mechanism, M_(cb), about the rotary axis108 is as shown in Equation 2:

M _(cb) =−k·a·b·sin(θ)   (2)

where k is the spring constant of spring 102.

Balancing the gravity load of the rotatable member 130 can be performedby matching the product of the three parameters k, a, and b to thegravity load, e.g., M_(grav)−M_(cb)=0 for all angles θ. By matching theproduct of k, a, and b with the parameter product of m, g, and L, thecounterbalance mechanism can balance the gravity load of the rotatablemember 130. As rotating member 130 rotates, the counterbalance mechanismproduces a sinusoidal, periodic torque that cancels the gravity torque;e.g., force applied to the rotating member is dynamically adjusted tocompensate for gravity as applied during the rotation.

FIG. 2 is a diagrammatic illustration of an example teleoperatedsurgical system 200 which can be used with one or more featuresdisclosed herein. Other types of control systems, teleoperated systems,or master-slave systems can be used in various implementations includingone or more described features. Teleoperated surgical system 200includes a user control system (e.g., surgeon's console) 202 and amanipulator system 204.

In this example, the user control system 202 includes a viewer 313(shown in FIG. 3 ) where an image of a worksite is displayed during anoperating procedure using the system 200. For example, the image can bedisplayed by a display device, such as one or more display screens, todepict a surgical site during a surgical procedure. A support 210 isprovided on which a user 212, e.g., an operator such as a surgeon, canrest forearms while gripping control input devices, such as controlinput devices 310 and 312 shown in FIG. 3 . The control input devices310 and 312 are positioned in a workspace 214 disposed inwardly beyondthe support 210. When using the user control system 202, the user 212can sit in a chair in front of the control system 202, position theuser's head/eyes in front of the viewer 313, and grip the control inputdevices 310 and 312, one in each hand, while resting forearms on thesupport 210. In some implementations of control system 202 and/orcontrol input devices 310 and 312, the user can stand while operatingthe control input devices.

A manipulator system 204 is also included in the teleoperated system200. For example, manipulator system 204 can be any type of devicecontrolled by a user control device or control input device. In someimplementations as shown, during a surgical procedure, the manipulatorsystem 204 can be positioned close to a surgical site located withreference to a patient or model disposed on an operating table or othertype of worksite). In various implementations, manipulator system 204can remain stationary until a particular procedure or stage of aprocedure is completed, or can move relative to a work site. Manipulatorsystem 204 can include one or more manipulator devices that can includemanipulator arm assemblies 220. In some examples, an arm assembly 220can include multiple links rotatably coupled to each other. Portions ofthe arm assembly 220 can be actuated with a motor and sensed aboutrotational axes. In some examples, one or more of the arm assemblies 220can be configured to hold a manipulator device such as an imagecapturing device, e.g., an endoscope 222, which can provide capturedimages of a portion of the surgical site. In some implementations, thecaptured images can be transmitted to the viewer 313 of the user controlsystem 202 and/or transmitted to one or more other displays, e.g., adisplay 224 coupled to the manipulator system 204.

In some examples, each of the other arm assemblies 220 may include amanipulator device such as a surgical tool 226. Each surgical tool 226can include a surgical end effector, e.g., for treating tissue of thepatient. For example, an end effector can include one or more motors orother actuators that operate associated features of the end effector,such as the pitch, yaw, and/or roll of the end effector, opening jaws ormoving a blade of the end effector, the output of material transportedthrough a connecting tube (e.g., liquid or other fluids), suctionforces, and/or any of a multiple of other end effector functions. Endeffector mechanisms can include flexible elements, articulated “snake”arms, steerable guide tubes, catheters, scalpel or cutting blade,electrical instruments, scissors, forceps, retractors, dilators, clamps,cauterizing tools, needles, staplers, drills, probes, scopes, lightsources, guides, measurement devices, vessel sealers, laparoscopictools, and/or other tip, mechanism or device. One example of a surgicalmanipulator arm is a da Vinci® surgical system instrument manipulatorarm in surgical systems commercialized by Intuitive Surgical, Inc. ofSunnyvale, Calif.

In this example, the arm assemblies 220 can be caused to move andarticulate the surgical tools 226 in response to manipulation ofcorresponding control input devices, e.g., control input devices 310 and312 at the user control system 202 by the user 212. This arrangementallows user 212 to, for example, direct surgical procedures at internalsurgical sites through minimally invasive surgical apertures. Forexample, one or more actuators coupled to the arm assemblies 220 canoutput forces to cause links or other portions of the arm assemblies tomove in particular degrees of freedom in response to control signalsreceived from the user control system 202. For example, movement of anarm and end effector in one or more degrees of freedom can correspond tomovement in one or more degrees of freedom of an associated controlinput device handle 310 or 312 by a user. The user control system 202can be used within a physical environment (e.g., an operating room) withthe manipulator system 104 or can be positioned more remotely from themanipulator system 202, e.g., at a different location than manipulatorsystem 204.

Some implementations of teleoperated system 200 can provide differentmodes of operation. In some examples, in a non-controlling mode (e.g.,safe mode) of teleoperated system 200, the controlled motion ofmanipulator system 204 is disconnected from the control input devices ofuser control system 202, such that movement and other manipulation ofthe control input devices does not cause motion of manipulator system204. In a controlling mode of teleoperated system 100 (e.g., followingmode, in which one or more controlled manipulators follow acorresponding control input device), motion of manipulator system 104can be controlled by control input devices 310 and 312 of the usercontrol system 202 such that movement and other manipulation of controlinput devices 310 and 312 causes motion of the manipulator system 204.The controlled functions of the manipulator device can include movementof the manipulator device. In some examples, the control input devicesare provided with the same degrees of freedom as manipulator devices ofthe manipulator system 204 to provide the user with telepresence.

Some implementations can be or include a teleoperated medical systemsuch as a da Vinci® Surgical System (e.g., a Model IS3000 or IS4000,marketed as the da Vinci Si® or da Vinci Xi® Surgical System),commercialized by Intuitive Surgical, Inc. of Sunnyvale, Calif. However,features disclosed herein may be implemented in various ways, includingin implementations at least partially computer-controlled, controlledvia electronic control signals, manually controlled via direct physicalmanipulation, etc. Implementations on da Vinci® Surgical Systems aremerely exemplary and are not to be considered as limiting the scope ofthe features disclosed herein. For example, different types ofteleoperated systems having controlled devices at worksites can make useof features described herein. Other, non-teleoperated systems can alsouse one or more described features, e.g., various types of controlsystems and devices, peripherals, etc.

For example, in various implementations, other types ofcomputer-assisted teleoperated systems can be used with one or morefeatures described herein, in addition to surgical systems. Suchteleoperated systems can include controlled manipulator devices ofvarious forms. For example, submersibles, hazardous material disposalunits, industrial applications, applications in hostile environments andworksites (e.g., due to weather, temperature, pressure, radiation, orother conditions), general robotics applications, and/or remote-controlapplications (e.g., remote controlled vehicle or device with afirst-person view), may utilize teleoperated systems that includecontrolled devices for sensory transmission (conveyed visual, auditory,etc. experience), manipulation of work pieces or other physical tasks,etc., and may use mechanically grounded and/or ungrounded control inputdevices to remotely control the manipulator devices. Any suchteleoperated systems can be used with the various features describedherein.

In some implementations, a controlled manipulator device can be avirtual representation of device, e.g., presented in a graphicalsimulation provided by a computing device coupled to the teleoperatedsystem 200. For example, a user can manipulate the control input devices310 and 312 of the user control system 202 to control a displayedrepresentation of an end effector in virtual space of the simulation,similarly as if the end effector were a physical object coupled to aphysical manipulator device.

FIG. 3 is a front elevational view of an example user control system 202as described above for FIG. 2 . User control system 202 includes aviewer 313 that provides a display of images of a worksite during aprocedure using the teleoperated system 200. The viewer 313 can bepositioned within a viewing recess 311 in which the user 212 canposition his or her head to view images displayed by the viewer 313.When using the user control system 202, the user 212 can sit in a chair(or stand) in front of user control system 202 and position his or herhead within the recess 311 such that his or her eyes are positioned infront of the viewer 313.

In some implementations, one or more user presence sensors 314 can bepositioned at one or more locations of the user control system 202 todetect the presence of a user's head located next to or near to the usercontrol system 202. In this example, the user presence sensors 314 cansense a presence of a user's head within recess 311. For example, anelectromagnetic sensor (e.g., optical sensor) can be used for a presencesensor. For example, if an emitted beam is interrupted from detection bythe detector, e.g., due to the user's head blocking the beam, then thesystem determines that the user is in a position to use the controlinput devices of the user control system 202.

Two control input devices 310 and 312 are provided for usermanipulation. In some implementations, each control input device 310 and312 can be configured to control motion and functions of an associatedarm assembly 220 of the manipulator system 204. For example, a controlinput device 310 or 312 can be moved in a plurality of degrees offreedom to move a corresponding end effector of the manipulator system204 in corresponding degrees of freedom. The control input devices 310and 312 are positioned in workspace 214 inwardly beyond the support 210.For example, a user 212 can rest his or her forearms while gripping thetwo control input devices 310 and 312, with one control input device ineach hand. The user also positions the user's head within the viewingrecess 311 to view the viewer 313 as described above while manipulatingthe control input devices 310 and 312.

Control input devices 310 and 312 may include an actuatable grip portion(e.g., handle) for actuating corresponding instruments of a manipulatorsystem, e.g., for closing grasping jaws, applying an electricalpotential to an electrode, delivering a medicinal treatment, and thelike. In some implementations, a grip function, such as moving two gripportions of a control input device together and apart in a pinchermovement, can provide an additional mechanical degree of freedom (i.e.,a grip DOF). In some example implementations, control input devices 310and 312 may provide control of one or more surgical instruments 226 in asurgical environment or proxy surgical instruments in a virtualenvironment. The control input devices may include any number of avariety of input devices manipulable by the user, such as kinematicallylinked (mechanically grounded) hand grips, finger grips, joysticks,trackballs, data gloves, trigger-guns, hand-operated controllers, voicerecognition devices, touch screens, and the like. Some examples of inputdevices that can be used as control input devices 310 and 312 aredescribed below.

In some implementations, control input devices 310 and 312 are manualinput devices which can be moved in all six Cartesian degrees of freedomby a user, including motion about axes 330 and 332. Control input device310 can be coupled to a control input arm assembly 320 that provides oneor more of the degrees of freedom to the control input device, andcontrol input device 312 can be similarly coupled to a control input armassembly 322. For example, control input arm assembly 314 and 316 caneach include a mechanical linkage that includes multiple membersrotatably coupled to at least one other of the members. Some examples ofa control input arm assembly are described below. In someimplementations, actuators such as motors can be included in or coupledto a control input arm assembly to output forces on the control inputdevice 310 or 312.

Some implementations of user control system 202 can include one or morefoot controls 328 positioned below the control input devices 310 and312, e.g., to input various commands to the teleoperated system whilethe user is operating the user control system 202.

FIG. 4 is a perspective view of a portion of a control input armassembly 400 that includes one or more counterbalance features describedherein, according to some implementations. In some implementations,control input arm assembly 400 can be included in a user control system,e.g., assembly 400 can be control input arm assembly 320 or 322 of usercontrol system 202 as described above in FIGS. 2 and 3 . Arm assembly400 includes a first member 402, a second member 404, a device linkage406, and a control input device 408.

First member 402 can be coupled at a proximal portion to a mechanicalground. For example, first member 402 can be rotatably coupled to asupport, housing, or other mechanically grounded component of a usercontrol system, e.g., user control system 202 of FIG. 2 . Second member404 is rotatably coupled at a proximal portion to a distal portion offirst member 402. In the configuration shown, first member 402 isapproximately vertically oriented and second member 404 is approximatelyhorizontally oriented when the assembly 400 is at rest or in a neutral,unused state.

Device linkage 406 is rotatably coupled at a proximal portion to adistal portion of second member 404. In some implementations, devicelinkage 406 can be a linkage of multiple members, where each member isrotatably coupled to at least one other of the members. In the describedimplementation, device linkage 406 includes a first link 412 and asecond link 414. A proximal portion of first link 412 is rotatablycoupled to a distal portion of second member 404. A proximal portion ofsecond link 414 is rotatably coupled to a distal portion of first link412. In some implementations as shown, first link 412 rotates about axis420 at its rotary coupling to second member 404, and second link 414rotates about axis 422 at its rotary coupling to first link 412, whereaxis 422 is orthogonal to axis 420.

Control input device 408 includes a support member 424 and a gripportion 426. Support member 424 that has a proximal portion rotatablycoupled to a distal portion of second link 414. In this example, supportmember 424 extends horizontally and vertically in an approximate “L”shape, and grip portion 426 is rotatably coupled to a distal portion ofmember 424. In the described implementation, member 424 rotates about anaxis 428 with respect to second link 414. Axis 428 is coincident withaxis 420 in the configuration shown in FIG. 4 . In some implementations,device linkage 406 forms or includes a gimbal mechanism that providesthree degrees of freedom to grip portion 426. Some examples of controlinput device 408 are described below with reference to FIG. 16 .

In some examples, grip portion 426 can be moved in a plurality ofdegrees of freedom, e.g., six degrees of freedom including threerotational degrees of freedom and three translational degrees offreedom. In some implementations, each degree of freedom of the gripportion 426 can control a different manipulator degree of freedom (orother motion) of an end effector of the manipulator system 204. One ormore degrees of freedom can be sensed by associated sensors and/oractuated by actuators (motors, etc.) (not shown).

Various sensors can be coupled to the members, links, control inputdevice, and/or other components of the assembly 400 and can detect theorientations and positions of these components of the assembly in theirdegrees of freedom. The sensors can send signals describing sensedpositions and/or motions to one or more control circuits of theteleoperated system 200. In some modes or implementations, the controlcircuits can provide control signals to a manipulator device, e.g.,manipulator system 204. For example, the orientations of the gripmembers 432 in their degrees of freedom can be used to control any ofvarious degrees of freedom of an end effector of the manipulator system204. In some examples, a position in a translational degree of freedomand/or orientation in a rotational degree of freedom can be derived fromrotations of components (e.g., links of the linkage including members402, 404, and 424 and links 412 and 414) as sensed by rotationalsensors. Some implementations can include linear sensors that candirectly sense translational motion of one or more components.

Various implementations of the assembly 400 can provide one or moreactive actuators (e.g., motors, voice coils, etc.) to output activeforces on the components of assembly 400. For example, a sensor and/oractuator can be housed in a housing of control input device 408 andcoupled to the grip members 432 by a transmission to output activeforces on grip members 432 in their rotational degrees of freedom. Someimplementations can provide one or more passive actuators (e.g., brakes)or springs between components to provide resistance in particulardegrees of freedom.

In this example, first member 402 can be oriented approximatelyvertically and second member 404 can be oriented approximatelyhorizontally as shown in FIG. 4 when in a non-operating state. Firstlink 412, second link 414, and member 424 can be oriented such thatfirst link 412 and second link 414 are to the left of control inputdevice 408 and to the left of a user's hand operating the control inputdevice 408, in the view of FIG. 4 . These members can be rotated toother orientations when the control input device 408 is moved in space,e.g., by a user. For example, the user's left hand can grasp controlinput device 408 and move control input device 408 in space, such thatthe links 412 and 414 and members 404 and 402 move to accommodate themotion of the control input device 408. Rotational sensors, e.g., withineach rotary coupling between the members and links, can measure therotation of each link and member such that the position, orientation,and motion of the control input device 408 is determined during usermanipulation of control input device 408.

In the described implementation, a counterbalance mechanism is coupledbetween first link 412 and second link 414 which counterbalances theforce of gravity exerted on the mass that is rotatably coupled to thedistal portion of first link 412. That mass includes second link 414 andcontrol input device 408. The center of gravity of this mass extendsaway from axis 422, first link 412, and second link 414 to the rear inthe view shown in FIG. 4 . This is due to the horizontal portion ofmember 424 extending in the rearward direction. This center of gravityis positioned such that gravity exerts a downward force on control inputdevice 408 and link 414 if these components are moved upward by the userin either rotational direction about axis 422 in the view shown in FIG.4 . The counterbalance mechanism opposes this downward gravity force.This allows the control input device 408 and link 414 to be moved withless required force from the orientation shown in FIG. 4 about axis 422,e.g., creating easier movement of these components by the hand of theuser and/or by actuators of the assembly 400.

In an example scenario, arm assembly 400 is one of two control inputassemblies installed in a user control system, such as control input armassemblies 320 and 322 of user control system 202 in FIG. 3 . Controlinput arm assembly 400 is configured to be positioned at the left sideof a user hand workspace such as workspace 214 for use with the user'sleft hand, e.g., the user's left hand is to grip the control inputdevice 408 similarly to control input device 310 of FIG. 3 .

In this scenario, arm assembly 400 has been installed at the right sideof workspace 214 and thus should be used with the user's right hand,e.g., the user's right hand is to grip the control input device 408similarly to control input device 312 of FIG. 3 . In some examples, armassembly 400 and all similar arm assemblies may have been received froma manufacturer or seller in the left-hand configuration, which allowsproduction and/or assembly costs of the arm assembly to be reduced. Inthis example, arm assembly 400 is installed in the right-hand locationof user control system 202, and is to be reconfigured from left-handeduse to right-handed use. This reconfiguration includes configuring thecounterbalance mechanism that is located between first link 412 andsecond link 414, as described in greater detail below.

FIGS. 5 and 6 are perspective views showing a counterbalance mechanism502 that can be used in the control input device arm assembly of FIG. 4, according to some implementations. FIG. 5 shows a portion of links 412and 414 of control input arm assembly 400, according to someimplementations, where an interior portion of link 412 and thecounterbalance mechanism 502 are exposed to view. FIG. 6 shows thecounterbalance mechanism 502 of FIG. 5 without the surrounding linkportions.

In some examples, a portion of the housing of first link 412 of devicelinkage 406 can be removed in preparation of reconfiguring thecounterbalance mechanism 502 for right-handed use. For example, screwsthat hold the cover in place can be removed and a cover lifted from thefirst link 412.

The interior of first link 412 includes counterbalance mechanism 502.Counterbalance mechanism 502 includes a joint gear 504, a configurablearm 506, a tension element 508, multiple counterbalance pulleysincluding first pulley 512, second pulley 514, and third pulley 516, acurved element 517, a guide pulley 518, and a counterbalance spring 520.

Joint gear 504 is a base element of counterbalance mechanism 502 and canbe rigidly coupled to a shaft 522 that is in turn rigidly coupled tosecond link 414. Joint gear 504 and shaft 522 are rotatable with respectto first link 412. Joint gear 504, shaft 522, and second link 414 thusrotate as a unit about axis 422 with respect to first link 412. In someimplementations, joint gear 504 can include multiple gear teeth on itscircumferential surface which engage other gear teeth of one or moregears coupled to an actuator 523 (e.g., motor) and/or sensor (e.g.,optical encoder or other sensor that senses rotation of a shaft). Inother implementations, a different base element can be used incounterbalance mechanism 502 instead of joint gear 504, e.g., a plate,cylinder, rectangular element, or other element that can engageconfigurable arm 506 similarly as described herein.

Configurable arm 506 includes a first portion and second portion, and isrotatably coupled to shaft 522 at the first portion (e.g., first end),and thus is rotatably coupled to joint gear 504. Configurable arm 506provides a rigid link between first counterbalance pulley 512 and secondcounterbalance pulley 514. The second portion (e.g., second end) ofconfigurable arm 506 is detachably coupled to joint gear 504 via anattachment mechanism (e.g., screw or pin in an aperture, or otherattachment mechanism) as described in greater detail below. Configurablearm 506 is located adjacent to joint gear 504 and its second portion issecured to joint gear 504 during operation of the counterbalancemechanism. Configurable arm 506 can be configured to a differentorientation to provide a different configuration of the counterbalancemechanism, as described in greater detail with respect to FIGS. 7A-11D.

First pulley 512 is rotatably coupled to the first portion (e.g., firstend) of configurable arm 506 at axis 422. First pulley 512 is rotatableabout axis 422 as its axis of rotation. First pulley 512 is rotatablycoupled to a mechanical ground via configurable arm 506 and shaft 522.

Second pulley 514 is rotatably coupled to the second portion (e.g.,second end) of configurable arm 506 and rotates about an axis 524, whereaxis 524 is parallel to axis 422 and is located offset from axis 422 bya particular distance, e.g., distance a shown in FIG. 1 . Thus, ifconfigurable arm 506 is rotated about axis 422, second pulley 514 orbitsaxis 422. In some examples, second pulley 514 is rotatably coupled to anend of configurable arm 506.

Third pulley 516 is rotatably coupled to first link 412, which acts as amechanical ground to the counterbalance mechanism. For example, thirdpulley 516 can be rotatably coupled to a frame portion 530 of first link412. Third pulley 516 rotates about an axis 525, which is locatedapproximately below the first pulley 512 as shown in FIGS. 5 and 6 .

A curved element 517 is rigidly coupled to mechanical ground (e.g., toframe portion 530) and is positioned adjacent to third pulley 516. Insome implementations, curved element 517 can be a cylindrical feature(or a partially cylindrical feature) that has a curved surface with thesame radius as pulley 516 and a center axis coincident with therotational axis 525 of third pulley 516. In some implementations, asshown in FIG. 6 , curved element 517 includes a curved surface aroundwhich tension element 508 can be wrapped, and can include a groovethrough which the tension element 508 is routed toward a groundedelement 534. In various implementations, curved element 517 can be afeature having a different shape or is an element that is a portion offrame portion 530 or first link 412.

Guide pulley 518 is rotatably coupled to first link 412, e.g., to frameportion 530 of first link 412. Guide pulley 518 rotates about an axis526, which in this example is nonparallel to axis 526 of third pulley516 as well as nonparallel to axes 422 and 524 of pulleys 512 and 514.The angled axis of rotation 526 allows guide pulley 518 to guide tensionelement 508 toward counterbalance spring 520, as described in greaterdetail below.

In some implementations, first pulley 512, second pulley 514, thirdpulley 516, and the curved surface of curved element 517 have the samediameter (e.g., same radius). Guide pulley 518 can also have the samediameter.

Counterbalance spring 520 can be located approximately below guidepulley 518 as shown in FIGS. 5 and 6 . In some implementations, spring520 can be located and oriented in a manner to allow it to fit withinthe housing of first link 412. For example, in the implementation ofFIG. 4 , first link 412 is curved, and spring 520 is angled to fitwithin the curved interior volume of first link 412.

A first end of spring 520 is mechanically grounded by being coupled tofirst link 412, e.g., to frame portion 531 that is coupled to link 412.A second end of spring 520 is coupled to tension member 508 and canprovide a spring force on the tension member. In some examples, asshown, the first end of spring 520 can be the further end of the springand the second end can be closer to guide pulley 518, such that thesecond end is moved away from the first end to provide tension viastretch of the spring. In other examples, the first end of spring 520can be the end closer to guide pulley 518 and the second end of spring520 is the further end at frame portion 531, such that the second end ismoved toward the first end to compress the spring.

Tension element 508 has a first end coupled to spring 520. Tensionelement 508 is routed from its first end at spring 520 to guide pulley518, where it wraps at least partially around guide pulley 518. Fromguide pulley 518, tension element 508 is routed to and at leastpartially wraps around third pulley 516. From pulley 516, tensionelement 508 is routed to and is wrapped at least partially around firstpulley 512 and then is routed to and is wrapped at least partiallyaround second pulley 514. Tension element 508 then is routed back towardthird pulley 516, where it wraps at least partially around the curvedsurface of curved element 517. Tension element 508 is anchored at itssecond end (e.g., at an opposite end to the first end of tension element508) to mechanical ground, e.g., coupled to grounded element 534 thatcan be coupled to frame portion member 530 and/or first link 412, orcoupled to curved element 517 that is rigidly coupled to first link 412.In various implementations, tension element 508 can be wrapped aroundcurved element 517 by a different amount depending on theimplementation, e.g., depending on the range of motion of second link414 and/or counterbalance arm 506.

FIG. 7A is a front view of counterbalance mechanism 502 in a firstconfiguration. In some implementations, this configuration can beoperated by a particular hand of a user of a control input device andarm assembly that is coupled to counterbalance mechanism 502. In someexamples, this configuration can be provided in control input armassembly 400 of FIG. 4 as arm assembly 310 of FIG. 3 that is operated bya left hand of a user.

Configurable arm 506 is rotatable about axis 422 to differentorientations, and this rotation can be used to configure thecounterbalance mechanism 502 to loads having different spatial locationsrelative to the counterbalance mechanism. For example, in FIG. 7A,configurable arm 506 is oriented in a first configuration orientation,which in this view is an orientation that is clockwise (e.g., a rightdirection) from a vertical orientation aligned with a vertical axis 532intersecting axis 422.

The first orientation shown in FIG. 7A is suited to counterbalancing amass that has a center of gravity 702 located on the opposite side ofaxis 422 from the second pulley 514, e.g., on the left side of verticalaxis 532 that intersects axis 422 in the view shown. For example, centerof gravity 702 can be the center of gravity of the mass that is coupledto joint gear 504 and rotates about axis 422. That mass includes secondlink 414 and control input device 408 as shown in FIG. 4 . Thecounterbalance mechanism 502 and center of gravity 702 can be oneimplementation of the counterbalance mechanism 100 shown in FIG. 1 .

In this example, an axis 704 intersects center of gravity 702, axis ofrotation 422 of first pulley 512, and axis of rotation 524 of secondpulley 514. Configurable arm 506 has a length defined by a first portionand a second portion, such that first pulley 512 is coupled to the firstportion at axis 422 and second pulley 514 is coupled to the secondportion (e.g., at a second end of the configurable arm). The length ofconfigurable arm 506 is aligned with axis 704 that intersects axis ofrotation 524, axis of rotation 422, and the center of gravity 702 of theload of the counterbalance mechanism.

Counterbalance mechanism 502 includes first pulley 512 and second pulley514 that are spaced apart by a distance A. First pulley 512 and thirdpulley 516 are spaced apart by a distance B. For example, thesedimensions can be based on the dimensions a and b as described abovewith reference to FIG. 1 to provide a counterbalance force on the masshaving center of gravity 702 to oppose the force of gravity on thatmass.

FIG. 7B is a front view of counterbalance mechanism 502 in a secondconfiguration. In some implementations, this configuration can be usedfor operation by a different hand of the user of a control input deviceof and arm assembly than the hand used for the first configuration shownin FIG. 7A. In some examples, the second configuration in control inputarm assembly 400 of FIG. 4 as arm assembly 312 of FIG. 3 that isoperated by a right hand of a user, as also shown in FIG. 12 .

In FIG. 7B, configurable arm 506 has been rotated counterclockwise withrespect to the first orientation shown in FIG. 7A, to be oriented in asecond configuration orientation, which in this view is counterclockwiseor in a left direction from a vertical orientation aligned with avertical axis intersecting axis 422.

Similarly to the first configuration of FIG. 7A, axis 704 intersectscenter of gravity 702, axis of rotation 422 of first pulley 512, andaxis of rotation 524 of second pulley 514. The length of configurablearm 506 is aligned with axis 704.

The second orientation as shown in FIG. 7B is suited to counterbalancinga mass that has center of gravity 702 located on the opposite side ofaxis 422 from the second pulley 514, e.g., on the right side of verticalaxis 532 that intersects axis 422 in the view shown. In this example,the counterbalance mechanism 502 is configured to counterbalance acenter of gravity 702 that has been approximately mirrored acrossvertical axis 532 extending through axis 422 from the orientation ofcenter of gravity 702 shown in the configuration of FIG. 7A. This issuitable for a right handed configuration of the control input device408, as shown in FIG. 12 .

Thus, counterbalance mechanism 502 can be configured for a left- orright-sided load center of gravity (e.g., on either side of verticalaxis 532) by orbiting second pulley 514 about axis 422, via the rotationof configurable arm 506, to the opposite side of vertical axis 532 fromthe center of gravity. Before and after this orbiting, the center of thesecond pulley is intersected by axis 704 that intersects the center ofgravity and axis 422. This configuration can be performed without havingto move the axis of rotation of other components such as third pulley516, and thus can accommodate centers of gravity that are located a fardistance or angle from the vertical axis 532 without having to provide alarger housing for the counterbalance mechanism. Furthermore, thetension of cable 508, as well as the stretch of the counterbalancespring 520 when the load is in a home position, remain the same in anyconfiguration of configurable arm 506, so that the same counterbalanceforce is consistently provided in the various configurations of thecounterbalance mechanism.

FIG. 8 is a front view of an example implementation of joint gear 504 ofthe counterbalance mechanism 502 described with reference to FIGS. 5-7B.Joint gear 504 is rigidly coupled to second link 414 and control inputdevice 408 as described above. In some implementations, joint gear 504includes gear teeth on its outer circumferential surface that engageother gear teeth of one or more gears coupled to an actuator, sensor,and/or mechanical element. Joint gear 504 can be a different baseelement in other implementations, as described above.

Joint gear 504 includes multiple engagement elements, where eachengagement element is associated with a particular configurationorientation of configurable arm 506 about axis 422. In the exampleimplementation of FIG. 8 , each engagement element is a configurationslot 802. Two configuration slots 802 a and 802 b are included in jointgear 504 as shown in FIG. 8. Each configuration slot 802 guides andengages the configurable arm 506 at its associated configurationorientation. For example, configuration slot 802 a engages theconfigurable arm 506 at the first configuration orientation describedwith reference to FIG. 7A. Configuration slot 802 b engages configurablearm 506 at the second configuration orientation described with referenceto FIG. 7B. In other implementations, different or additional engagementelements can be provided at different configuration orientations aboutaxis 422. For example, an engagement element can be a plug element orextension that extends from the surface of joint gear 504, or otherfeature that can be engaged with and/or secured to configurable arm 506.

In some implementations, configuration slots 802 a and 802 b arerecessed into a raised portion 804 of the joint gear 504. For example,portion 804 of joint gear 504 can be raised above or extend past asurface of base portion 806 of joint gear 504. For example, base portion806 can include gear teeth in some implementations, as shown in FIG. 8 .Slots 802 are approximately rectangular in the example of FIG. 8 , butcan have other shapes in other implementations (e.g., triangular,hexagonal, etc.).

In some implementations, slots 802 can have one or more tapered sides808, e.g., sloped or beveled slides of each slot 802 that slope from thetop of portion 804 toward a center of the slot 802. The tapered slidesof a slot 802 can assist and guide the configurable arm 506 to slideinto an orientation about axis 422 in which it can engage with the slot.

In the example implementation, each slot 802 includes an aperture 812,which can be used to secure configurable arm 506 to joint gear 502. Forexample, each aperture 812 can be a threaded aperture that can receive abolt or screw, e.g., the bolt described with respect to FIG. 10 .

Joint gear 504 includes multiple stop members 810, each of which can beused to assist and/or guide configurable arm 506 into the slot 802associated with the stop member 810. For example, two stop members 810 aand 810 b are shown in FIG. 8 . Each stop member 810 includes aprotrusion raised above the surface of portion 804 of the joint gear 504in the path of rotation of configurable arm 506 about axis 422.

Each stop member 810 provides a stop to the rotation of the configurablearm 506 about axis 422 in a particular direction, e.g., when rotatingconfigurable arm 506 from one configuration orientation to anotherconfiguration orientation. The stop members 810 are located such thatthe configurable arm 506 can be engaged, at the stopped orientation,with the slot 802 located at that configuration orientation. Forexample, stop member 810 a stops rotation of configurable arm 506 in aclockwise direction at an orientation that is aligned or approximatelyaligned to the first configuration orientation described with referenceto FIG. 7A, and the configurable arm 506 can then be engaged with slot802 a (e.g., guided by a guide member of arm 506 as described below) toobtain the first configuration orientation. Stop member 810 b stopsrotation of configurable arm 506 in a counterclockwise direction at anorientation that is aligned or approximately aligned to the secondconfiguration orientation described with reference to FIG. 7B, and theconfigurable arm 506 can then be engaged with slot 802 b (e.g., guidedby the guide member of arm 506) to obtain the second configurationorientation. In other implementations, different types of stop memberscan be provided at different configuration orientations about axis 422.

FIGS. 9A, 9B, and 9C are front, side cross-sectional, and perspectiveviews, respectively, of an example configurable arm 506 that can be usedin one or more implementations described herein. Configurable arm 506can include an extended portion 902 that can act as a hub to which thesecond pulley 514 is rotatably coupled. For example, second pulley 514can include a pulley portion 904 and a bearing 906, where bearing 906 isrigidly coupled to extended portion 902 and pulley portion 904 isrotatably coupled to bearing 906. Bearing 906 can be a ball bearing orother rotatable bearing that allows pulley portion 904 to rotate aboutaxis 522 with respect to extended portion 902 and configurable arm 506.

In some implementations, first pulley 512 can be rotatably coupled toshaft 522. For example, first pulley 512 can include a pulley portion908 and a bearing 910, where bearing 910 is rigidly coupled to shaft 522and pulley portion 908 is rotatably coupled to bearing 910. Bearing 910can be a ball bearing or other rotatable bearing that allows pulleyportion 908 to rotate about axis 422 with respect to shaft 522 andconfigurable arm 506.

Configurable arm 506 includes a shaft aperture 912 that can receive ashaft and a bolt aperture 914 that can receive a bolt or similarattachment member. In an example implementation (e.g. as shown in FIGS.5-8 ), configurable arm 506 can be rotatably coupled to shaft 522 thatextends through shaft aperture 912 such that configurable arm 506 canrotate about axis 422 as shown in FIGS. 7A and 7B.

An attachment mechanism can be used to secure configurable arm 506 tojoint gear 504. In some implementations, the attachment mechanism caninclude an attachment member such as bolt 915 (shown in dotted lines inFIG. 9B) and threaded apertures 812 of joint gear 504, where bolt 915 isinserted through bolt aperture 914 and into one of the threadedapertures 812 of joint gear 504 to secure configurable arm 506 in aparticular configuration orientation. One example of such a bolt is bolt1000 described with respect to FIG. 10 .

In some implementations, bolt aperture 914 can include a threadedportion 916 and a clearance portion 918, where threaded portion 918 iscloser than threaded portion 916 to the surface 922 of configurable arm506 that faces joint gear 504. When inserting bolt 915, a threadedportion of the bolt can be threaded through threaded portion 916, movedthrough clearance portion 918, and threaded into a threaded aperture 812of joint gear 504. When removing the bolt to allow configurable arm 506to be rotated to a different configuration orientation, the threadedportion of the bolt can be unthreaded and moved away from the threadedaperture 812 so that the threaded portion of the bolt is positioned atleast partially within clearance portion 918 of bolt aperture 914.

In some implementations, configurable arm 506 can include a guideportion that engages the engagement element (e.g., slot 802) at eachconfiguration orientation of joint gear 504. In the exampleimplementation, the guide portion of arm 506 is a plug portion 920 thatcan engage any of slots 802 of joint gear 504. In other implementations,the guide portion can be a different engagement element, e.g., a slot inconfigurable arm 506 that can be engaged by a plug element of joint gear504 or coupled to joint gear 504, or other feature that can be securedto each engagement element of joint gear 504.

Plug portion 920 is an extended portion of arm 506 that is located onthe side of configurable arm 506 facing joint gear 504 and opposite thethreaded portion 916 of bolt aperture 914. Plug portion 920 can surroundclearance portion 918 of bolt aperture 914. Plug portion 920 is sizedand shaped to be inserted into any of the slots 802 of joint gear 504 toengage configurable arm 506 with joint gear 504 at one of theconfiguration orientations. For example, plug portion 920 fits within aslot 802 such that an engaging surface of plug portion 920 contacts theflat bottom surface of the slot 802 and a surface 922 of configurablearm 506 contacts portion 804 of the joint gear 504. In someimplementations, plug portion 920 is a tapered element includingmultiple tapered sides 924 that assist and guide the configurable arm506 into a slot 802. In some implementations, tapered sides 924 contactand engage tapered sides 808 of slot 802.

In some implementations, configurable arm 506 can include one or moreslots 930 to assist a user in separating configurable arm 506 from jointgear 504. For example, each slot 930 can be configured to receive aseparation tool to move (e.g., slide or pry) the configurable arm awayfrom the base element. In some examples, the user can insert theseparation tool that has a portion that fits within a slot 930 to bepositioned between the configurable arm 506 and joint gear 504, suchthat the user can pull on an extended portion of the separation tool(extending out of slot 930) to contact and force the tool against thejoint gear 504 and slide or pry the configurable arm 506 along shaft 522and away from joint gear 504. Slots 930 can be located on configurablearm 506 close to shaft aperture 912 (e.g., located on an edge of thefirst portion or first end of configurable arm 506, that is between theshaft aperture 912 and bolt aperture 914). This location reduces thetendency of arm 506 to tilt and bind on shaft 522 when arm 506 is pulledalong the shaft, which may happen more readily if configurable arm 506is pulled at locations further away from shaft 522. In someimplementations, slots 930 are shaped and configured to receive an endof a particular user-manipulated tool (e.g., wrench, etc.) that can alsofit into the head of bolt 915 (or bolt 1000) and allow the user to screwor unscrew the bolt.

Different forms of configuration arm 506 can be used in otherimplementations, e.g., having a different shape, engagement elements,and/or attachment mechanism to secure the configuration arm in aconfiguration orientation for use in counterbalance mechanism 502. Forexample, the engagement element and/or attachment mechanism can includean aperture or slot in configuration arm 506 that can engage a pin,screw, or other engagement element of joint gear 504.

FIG. 10 is a side elevational view of an example bolt 1000 that can beused to secure configuration arm 506 to joint gear 504. Bolt 1000includes a head portion 1002 and a threaded portion 1004. Bolt 1000 canbe inserted in bolt aperture 914 shown in FIG. 9 and screwed into one ofthe threaded apertures 812 of the joint gear 504 to secure theconfiguration arm 506 to a particular configuration orientation aboutaxis 422. Head portion 1002 engages a surface of configuration arm 506that is opposite to surface 922 when the bolt 1000 is fully inserted inbolt aperture 914. In other implementations, other types of attachmentelements instead of bolt 1000 can be used in an attachment mechanism tosecure configurable arm 506 to joint gear 504.

FIGS. 11A-11D are perspective views of a portion 1100 of counterbalancemechanism 502 including joint gear 504 and configurable arm 506 in whicharm 506 is in different orientations and positions, according to someimplementations. These views show an example of configurable arm 506being changed from one configuration orientation to a differentconfiguration orientation.

In FIG. 11A, configurable arm 506 is oriented at the first configurationorientation as described with reference to FIG. 7A. In this example, arm506 is fully engaged with joint gear 504 by bolt 1000 that secures arm506 to the joint gear 504, e.g., the plug portion 920 of configurablearm 506 is engaged with (seated in) slot 802 a of joint gear 504 andbolt 1000 is screwed into threaded aperture 812 in slot 802 a. Asdescribed above, in some implementations this first configurationorientation can be used for a left-handed configuration of control inputarm assembly 400 of FIG. 4 .

In FIG. 11B, configurable arm 506 has been pulled from slot 802 a ofjoint gear 504 with respect to its secured position shown in FIG. 11A,to a disengaged position. Arm 506 has been pulled along axis 422 awayfrom joint gear 504, e.g., along shaft 522 that couples thecounterbalance mechanism 502 to second link 414. In some examples, arm506 is moved along a shaft in a direction along axis 422 andperpendicular to a plane of rotation of the configurable arm. To obtainthis position of arm 506, bolt 1000 is unscrewed from threaded aperture812 in slot 802 a and the bolt is pulled away from slot 802 a (e.g.,along axis 524) such that it is retracted at least partially intoclearance portion 918 of configurable arm 506 sufficiently such that thebolt clears the sides of slot 802 a. Configurable arm 506 is pulled awayfrom slot 802 a on shaft 522 sufficiently such that the engaging side ofconfigurable arm 506 clears the sides of the slot 802 a and the arm 506can be rotated about axis 422. For example, in some implementations, theuser can insert a tool into a slot 930 (or two tools into both slots930) of configurable arm 506 to assist the user in pulling configurablearm 506 away from slot 802 a.

In FIG. 11C, configurable arm 506 has been rotated from its orientationshown in FIG. 11B. For example, arm 506 is rotated counterclockwiseabout axis 422 to obtain the orientation shown in FIG. 11C that isaligned or approximately aligned with the second configurationorientation designated by slot 802 a of joint gear 504. In someimplementations, the user can rotate configurable arm 506counterclockwise until arm 506 is stopped by stop member 810 b at anorientation that is aligned or approximately aligned with the secondconfiguration orientation.

In FIG. 11D, configurable arm 506 has been moved with reference to FIG.11C to a secured position at the second configuration orientation asdescribed with reference to FIG. 7B. In this example, arm 506 is fullyengaged with joint gear 504 by bolt 1000 that secures arm 506 to thejoint gear 504, e.g., the plug portion 920 of configurable arm 506 isengaged with slot 802 b of joint gear 504 and bolt 1000 is screwed intothreaded aperture 812 in slot 802 b along axis 514. As described above,in some implementations this first configuration orientation can be usedfor a right-handed configuration of control input arm assembly 400 ofFIG. 4 .

To obtain the second configuration orientation and secured position ofarm 506, a user can push the configurable arm 506 along shaft 522 fromits position of FIG. 11C into slot 802 b of joint gear 504. The taperedsides 924 of plug portion 920 of configurable arm 506 can contacttapered sides 808 of slot 802 b such that these tapered sides 924 and808 guide plug portion 920 into slot 802 b, thus precisely guidingconfigurable arm 506 to the second configuration orientation (relativeto the more approximate alignment to the second configurationorientation obtained by moving configurable arm 506 against stop member810 b shown in FIG. 11C). After full insertion into slot 802 b such thatplug portion 920 is seated in (engaged with) slot 820 b, the user canscrew bolt 1000 into threaded aperture 812 in slot 802 b such that theconfigurable arm 506 is secured in slot 802 b.

A similar procedure in reverse of the process shown in FIGS. 11A to 11Dcan be performed, e.g., to change the configurable arm 506 from thesecond configuration orientation to the first configuration orientation,including moving the arm 506 in a clockwise direction about axis 422.

In various implementations, other or additional configurationorientations can be provided in a counterbalance mechanism. For example,a configuration orientation can be provided that counterbalances a masshaving a center of gravity that is slightly different than center ofgravity 702, e.g., has a different orientation about axis 422 than thecenter of gravity 702 shown in FIG. 7A but not as large a difference inorientation as the center of gravity 702 of FIG. 7B at the opposite sideof the counterbalance mechanism. For example, a different control inputdevice, or component thereof, could be used in control input armassembly 400 in place of the control input device 408 or component thatprovides the center of gravity 702 of FIG. 7A. In some examples of theseimplementations, a third configuration orientation can be providedclockwise or counterclockwise about axis 422 from the firstconfiguration orientation, and can have its own associated slot 802,threaded aperture 812, and (removable) stop member 810 (e.g., replacingor provided in addition to the second configuration orientation slot802). In some examples, the configurable arm 506 can be moved to thethird configuration orientation if the associated component is attachedto the control input arm assembly 400.

In some implementations, configuration of counterbalance mechanism 502can also be performed by adjusting other components of thecounterbalance mechanism. For example, the distance A between firstpulley 512 and second pulley 514 (shown in FIG. 7A) can be adjusted,e.g., by moving second pulley 514 along axis 704 and along configurablearm 506. For example, such an adjustment of a pulley can counterbalancea different load that is heavier or lighter than the load having centerof gravity 702, e.g., a different load that has the same orientation ofcenter of gravity 702 about axis 422 (a tension element 508 of differentlength may be used in some implementations). In some implementations,third pulley 516 can be moved. For example, third pulley 516 can beslidably coupled ground member 530, e.g., slidable within a groove orchannel of the ground member. The third pulley 516 can be slid to eitherend of the channel to configure counterbalance mechanism 502 tocounterbalance masses having centers of gravity at differentorientations about axis 422.

In some implementations, a doubled tension element (e.g., doubled cable)can be used in some implementations of counterbalance mechanisms thatinclude one or more features described herein. For example, a doubledtension element can be used in place of the single tension element 508shown in FIGS. 5-8 . In some examples, two cables routed side-by-sidecan have one end coupled to spring 520 and their other ends coupled toground at grounded element 534.

FIG. 12 is a perspective view of the portion of control input armassembly 400 of FIG. 4 in which arm assembly 400 has been reconfiguredfrom its left-handed configuration to a right-handed configuration,according to some implementations. In some examples as shown in FIGS.4-11D, configurable arm 506 of counterbalance mechanism 502 in firstlink 412 has been moved from the first configuration orientation at slot802 a of joint gear 504 to the second configuration orientation at slot802 b of joint gear 504, as shown in FIGS. 11A-11D.

After this reconfiguration of configurable arm 506, housing of armassembly 400 can be replaced and the links of arm assembly 400 can berotated to obtain the right-handed configuration. For example, a usercan rotate the links manually or actuators in one or more links can becontrolled by a control system to move the links. As shown in FIG. 12 ,in the right-handed configuration, first link 412 has been rotated 180degrees from its position shown in FIG. 4 , which causes second link 414to also be rotated 180 degrees since it is supported by first link 412.Control input device 408 is rotated 180 degrees about axis 428 withreference to first link 412 and second link 414 (e.g., is not rotatedwith respect to members 402 and 404 of arm assembly 400), to maintain anorientation that is similar to its orientation in the left-handedconfiguration shown in FIG. 4 with reference to first member 402 andsecond member 404. Control input device 408 is thus oriented to be usedby a right hand of the user, with first link 412 and second link 414 onthe outside (e.g., to the right) of the user's hand.

FIG. 13 is a front view of an example of counterbalance mechanism 502showing planar counterbalance features, according to someimplementations. FIG. 14 is a cross section of some components ofcounterbalance mechanism 52 as cut by an active plane of counterbalancemechanism 502. These figures show some implementations of acounterbalance mechanism, which can be mechanism 502 and othercounterbalance mechanisms, that include one or more features thatprovide active counterbalance components in a single plane. Suchfeatures allow, for example, more accurate counterbalance forces to beapplied to a load.

In the implementation of FIGS. 13-14 , first and second pulleys 512 and514 have axes of rotation 422 and 524 that are parallel. Third pulley516 has an axis of rotation 525 that is nonparallel to the axes ofrotation 422 and 524 of the first and second pulleys 512 and 514. Thirdpulley 516 has been angled or tilted such that tension element 508 makescontact with third pulley 516 and curved element 517 in a single plane1302 that also includes the first and second pulleys 512 and 514. Thus,plane 1302 is orthogonal to first pulley axis 422 and second pulley axis524, and axis of rotation 525 of third pulley 516 is at a non-orthogonalangle with reference to plane 1302.

For example, in a path of tension element 508 from its first end atcounterbalance spring 520 to its second end at grounded element 534,tension element 508 wraps around third pulley 516 and exits the thirdpulley 516 at a point C. After wrapping around first and second pulleys512 and 514, tension element 508 enters contact with curved element 517at point D and wraps around a curved surface 1402 of element 517 beforebeing coupled to grounded element 534 (FIG. 14 shows third pulley 516,curved element 517, and guide pulley 518 partially due to thecross-sectional view based on plane 1302). In the example shown in FIG.14 , tension element 508 is anchored to grounded element 534 by a ballclip 1404; other attachment mechanisms can be used in otherimplementations.

To cause these planar exit and entrance of the tension element 508,third pulley 516 is angled such that a side of pulley 516 closer topoint C is positioned within plane 1304 (and thus appears in FIG. 14 )and a side of pulley 516 closer to point D is higher, e.g., further fromand out of plane 1302 (and thus does not appear in FIG. 14 ). Theout-of-plane side of third pulley 516 is further from the surface offrame portion 530 and thus allows curved element 517 to be located at ahigher position, further from frame portion 530 and within plane 1304,than if axis 525 of pulley 516 were parallel to the other pulley axes422 and 524.

The moment applied by a counterbalance mechanism 502 (and the mechanismas shown in FIG. 1 ) is M_(cb)=K*A*B*Sin(θ), which perfectly counteractsthe moment load caused by gravity only if several conditions are met.These conditions include the spring rate, the initial tension of thesystem, and the active length of the tension element 508 are all in asingle plane as indicated by plane 1302. Angling third pulley 516 asshown provides this active length of tension element 508 in a singleplane. The other portions of tension element 508 (e.g., the lengthwrapping around the lower half of third pulley 516, the length wrappingaround guide pulley 518, and the length extending to spring 520) are notconsidered in the counterbalance force determination, and so theseportions need not be in the single plane 1302.

The curved surface 1402 of curved element 517 can be angled at the sameangle as the circumferential sides of third pulley 516 that engagetension element 508. For example, a center orthogonal axis located at aradius of curved surface 1402 of curved element 517 can have the sameangle as axis of rotation 525 of third pulley 516. For example, ifcurved element 517 is implemented as a cylinder (stationary pulley), thecentral axis of the cylinder is oriented in parallel to (and/or alignedwith) the rotation axis 525 of third pulley 516.

The angle of third pulley 516 causes the active portions of the tensionelement 508 to be within plane 1304, the active portions being theportions of tension element 508 between first pulley 512, second pulley514, and the points C and D as shown. This allows the moment load of thecounterbalance and the moment load from gravity to cancel out for allpossible angles. Since the determination of counterbalance forces fromcounterbalance mechanisms often assumes, ideally, that these activeportions are in a single plane, the angle of third counterbalance pulley516 provides counterbalancing performance that is closer to the idealdesign, e.g., such that an appropriate sinusoidal force is produced tocounterbalance gravity forces at any rotational angle of the load aboutaxis 422. This planar feature allows a counterbalance mechanism toprovide counterbalance forces that more accurately reduce or cancelgravity force on a load.

In some previous implementations, active portions of a tension element(including entry and exit) were not in a single plane because astationary curved element was at a different level than the third pulley(e.g., adjacent to the third pulley) and the third pulley was notangled. Thus, the path of the tension element traced into threedifferent planes, e.g., from one level of the curved element, to a levelof the first and second pulleys 512 and 514, to a level of the thirdpulley 516. This caused the counterbalance mechanism to produceinappropriate counterbalance forces at some load angles where thecounterbalance force did not fully cancel the gravity force on the loadat all rotational orientations of the load. The model of thecounterbalance mechanism assumed there was no offset or change in levelof the different pulleys and elements.

Counterbalance mechanism 502 can also, in some implementations, providethe axis of rotation 526 of guide pulley 518 at an angle such that axis526 is nonparallel to the rotation axes 422, 524, and/or 525 of theirrespective pulleys. The angle of guide pulley 518 can be arranged toroute tension element 508 toward spring 520. Spring 520, for example,may be positioned and/or oriented at an angle offset from pulleyrotation axes so that spring 520 can fit in available space of a housingof the arm assembly 400.

The angle of guide pulley 518 can be arranged to reduce or eliminate anyfleet angle of tension member 508 that may exist going into or out ofthird pulley 516. The fleet angle is the angle at which a tension membersuch as a cable engages with (e.g., enters or exits) a pulley, asreferenced from the center axis of the pulley. Guide pulley 518 can beangled such that tension member 508 engages the third pulley 516 and theguide pulley 518 at zero (or close to zero) angle offset from the centerof the engaging circumferential surface or side of these pulleys. Suchreduced fleet angle can reduce or eliminate friction provided from theengagement between tension member 508 and pulleys 516 and 518. Theplanar positioning of the entry and exit points C and D for third pulley516 can also reduce the fleet angle of tension member 508 engaging withthird pulley 516 and/or with curved element 517.

FIG. 15 is a flow diagram illustrating an example method 1500 toconfigure a counterbalance mechanism, according to some implementations.Method 1500 can, for example, be performed using counterbalancemechanism 502, any of the example counterbalance mechanisms describedherein, or other counterbalance mechanisms. In some implementations, thecounterbalance mechanism is coupled to or included in a mechanical armassembly, such as arm assembly 400 as shown in FIG. 4 that can beincluded in a user control system 202 of FIG. 2 . Other implementationscan use a counterbalance mechanism provided in other types of mechanicalsystems, e.g., non-teleoperated systems.

In block 1502, a configurable arm of a counterbalance mechanism isoriented at a first configuration orientation and engaged with a baseelement. For example, as described in examples herein, configurable arm506 of counterbalance mechanism 502 can be oriented in a firstconfiguration orientation in which arm 506 is engaged with and securedto a base element that is joint gear 504. As shown in some examplesherein, the first configuration orientation can be associated with aparticular handedness of a control input device. For example, as shownin FIGS. 4 and 12 , the first configuration orientation can be used withleft-handed configuration of an arm assembly for use with a user's lefthand. The method continues to block 1504.

In block 1504, an attachment mechanism that secures the configurable armto the base element is disengaged. In some examples described above, theattachment mechanism includes a bolt 1000 that is unscrewed fromthreaded aperture 812 in slot 802 a of joint gear 504. The methodcontinues to block 1506.

In block 1506, the configurable arm is moved away from the base elementalong a shaft. In some implementations, a guide portion of theconfigurable arm disengages an engagement element of the base element.In some examples, plug portion 920 of configurable arm 506 disengagesfrom a slot 802 of joint gear 504 and configurable arm 506 is slid alongshaft 522 to a disengaged position along shaft 522, e.g., as shown inFIG. 11B. In some examples, a user can insert a tool in a slot 930 toassist sliding the configurable arm along the shaft without binding. Forexample, the configurable arm can be moved along the shaft in adirection\perpendicular to a plane of rotation of the configurable arm.The method continues to block 1508.

In block 1508, the configurable arm is rotated toward targetconfiguration orientation and against a stop member in the range ofmotion about an axis of rotation of the arm. In some implementations, asdescribed above, the stop member is located such that the configurablearm is stopped at an orientation that is aligned or approximatelyaligned with the second configuration orientation of the base element.For example, if in block 1506 the configurable arm was moved out of thefirst configuration orientation of FIG. 11A, the configurable arm isrotated counterclockwise to a stopped orientation against stop member910 b, as shown in FIG. 11C. If in block 1506 the configurable arm wasmoved out of the second configuration orientation of FIG. 11D, theconfigurable arm is rotated clockwise (e.g., by a user) to a stoppedorientation against stop member 910 a, as shown in FIG. 11B. The stopmember aligns the configurable arm and also provides a safety stop tothe arm to prevent it from rotating past the target configurationorientation. The method continues to block 1510.

In block 1510, the configurable arm is moved toward the base element toengage the base element at the target configuration orientation. Forexample, configurable arm can be pushed by a user along shaft 522 towardjoint gear 504 such that plug portion 920 of the configurable arminserts into slot 802 b at the second configuration position, as shownin FIG. 11D. The method continues to block 1512.

In block 1512, the attachment mechanism is engaged to secure theconfigurable arm to the base element at the second configurationposition. In some examples, the attachment mechanism includes bolt 1000that is screwed into threaded aperture 812 in slot 802 b of joint gear504. In some examples as described for FIGS. 4 and 12 , the controldevice can then be operated in a right-handed configuration with thecounterbalance mechanism 502 correctly balancing the gravity forces onthe control input device 408 and second link 414.

It should be noted that the blocks described in the methods disclosedherein can be performed in a different order than shown and/orsimultaneously (partially or completely) with other blocks, whereappropriate. Further, not all of the described blocks need be performedin various implementations. In some implementations, blocks can beperformed multiple times, in different orders, and/or at different timesin the methods.

FIG. 16 is a perspective view of an example control input device 1600which can be used in conjunction with one or more features describedherein. In some implementations, control input device 1600 can becontrol input device 408 as described above with reference to FIGS. 4and 12 . For example, user input can be provided via control inputdevice 1600 to control one or more controllable device functions. Forexample, in a teleoperated system, the control input device can controla manipulator device as described above, or can be included in adifferent control system.

Control input device 1600 can include support member 1602 (e.g., similarto support member 424 of FIG. 4 ) and grip portion 1604 (e.g., similarto grip portion 426 of FIG. 4 ). Support member 1602 extendshorizontally and vertically in an approximate “L” shape, and gripportion 1604 is rotatably coupled to member 1602. In the describedimplementation, support member 1602 rotates about an axis 1603 withrespect to a link 1606, which can be similar to second link 414 of FIG.4 in some implementations. Axis 1603 can be similar to axis 428 shown inFIG. 4 .

Grip portion 1604 is contacted by a user to manipulate the control inputdevice. Grip portion 1604 includes two grip members 1610 (grip members1610 a and 1610 b ) that each include a finger loop 1612. The two gripmembers 1610 are positioned on opposite sides of a central portion 1614of the grip portion 1604, and the grip members 1610 can be grasped,held, or otherwise contacted by a user's fingers. Each finger loop 1612can secure a user's fingers to the associated grip member 1610. Eachgrip member 1610 is rotatably coupled to central portion 1614 andpivoted in a respective rotational degree of freedom 1616 a and 1616 b.For example, the grip members 1610 can be pivoted simultaneously in apincher-type of movement. In some examples, the orientations of gripmembers 1610 in their degrees of freedom can control correspondingrotational positions of an end effector or component thereof of amanipulator system 204. Grip portion 1604 can be provided with arotational degree of freedom 1618 about a longitudinal roll axis 1620that extends approximately along the center of the central portion 1614of grip portion 1604.

In some implementations, one or more grip sensors can be coupled to thegrip portion 1604 and/or other components of device 1600 and can detectorientations of the grip members 1610 a and 1610 b in their degrees offreedom 1616. The grip sensors can send signals describing sensedorientations and/or motions to one or more control circuits of theteleoperated system 200. In some implementations, the control circuitscan provide control signals to a manipulator device, e.g., manipulatorsystem 204. Various implementations of the control input device 1600 canprovide one or more active actuators (e.g., motors, voice coils, etc.)to output active forces on the grip members 1610 in the degrees offreedom 1616. For example, a sensor and/or actuator can be housed incentral portion 1614 or in a housing of support member 1602 and can becoupled to the grip members 1610 by a transmission. Some implementationscan provide one or more passive actuators (e.g., brakes) or springs toprovide resistance in particular directions of the grip members 1610.Similarly, one or more sensors can be coupled to the grip portion 1604to detect the orientation of the grip portion in the rotational degreeof freedom 1618. Some implementations of the control input device 1600can provide one or more actuators to output forces on the grip portion1604 (including grip members 1610) in the rotational degree of freedom1618.

FIG. 17 is a block diagram of an example control system 1700 which canbe used with one or more features described herein. System 1700 includesa user control device 1702 that a user may manipulate in order tocontrol a controlled device 1704 in communication with the user controldevice 1702. In some implementations, user control device 1702 can be,or can be included in, user control system 202 of FIG. 2 . In someimplementations, controlled device 1704 can be, or can be included in,manipulator system 204 of FIG. 2 . More generally, user control device1702 can include, or be a portion of, any type of control input devicethat can be physically manipulated by a user (e.g., control input device408). User control device 1702 generates control signals C1 to Cxindicating positions, states, and/or changes of one or more controlinput devices in their degrees of freedom. The user control device 1702can also generate control signals (not shown) indicating selection ofphysical buttons and other manipulations by the user.

A control block 1710 can be included in the user control device 1702, inthe controlled device 1704, or in a separate device, e.g., anintermediary device between user control device 1702 and controlleddevice 1704. In some implementations, the control block 1710 can bedistributed among multiple of these devices. Control block 1710 receivescontrol signals Cl to Cx and generates actuation signals A1 to Ay, whichare sent to controlled device 1704. Control block 1710 can also receivesensor signals B1 to By from the controlled device 1704 that indicatepositions, states, and/or changes of various components of thecontrolled device (e.g., manipulator arm members, instruments, or otherelements). Control block 1710 can include general components such as aprocessor 1712, memory 1714, and interface hardware 1716 and 1718 forcommunication with user control device 1702 and controlled device 1704,respectively. Processor 1712 can execute program code and control basicoperations of the system 1700, including functions related to sensingorientations of arm members and sending signals to control motors asdescribed herein, and can include one or more processors of varioustypes, including microprocessors, application specific integratedcircuits (ASICs), and other electronic circuits. Memory 1714 can storeinstructions for execution by the processor and can include any suitableprocessor-readable storage medium, e.g., random access memory (RAM),read-only memory (ROM), Electrical Erasable Read-only Memory (EEPROM),Flash memory, etc. Various other input and output devices can also becoupled to the control block 1710, e.g., display(s) 1720 such as theviewer 1713 of the user control system 202 and/or display 224 of FIGS. 2and 3 .

In this example, control block 1710 includes a mode control module 1740,a controlling mode module 1750, and a non-controlling mode module 1760.Other implementations can use other modules, e.g., a force outputcontrol module, sensor input signal module, etc. In someimplementations, the modules 1740, 1750, and 1760 can be implementedusing the processor 1712 and memory 1714, e.g., program instructionsstored in memory 1714 and/or other memory or storage devices connectedto control block 1710.

Mode control module 1740 can detect when a user initiates a controllingmode and a non-controlling mode of the system, e.g., by user selectionof controls, sensing a presence of a user at a user control system orcontrol input device, sensing required manipulation of a control inputdevice, etc. The mode control module can set the controlling mode or anon-controlling mode of the control system 1710 based on one or morecontrol signals C1 to Cx.

In some implementations, controlling mode module 1750 may be used tocontrol a controlling mode of control block 1710. Controlling modemodule 1750 can receive control signals C1 to Cx and can generateactuation signals A1 to Ay that control actuators of the controlleddevice 1704 and cause it to follow the movement of user control device1702, e.g., so that the movements of controlled device 1704 correspondto a mapping of the movements of user control device 1702. Controllingmode module 1750 can also be used to control forces on the user controldevice 1702, e.g., forces output on one or more components of the armassembly of the user control device, e.g., base element, arm members,grip members, etc., using one or more control signals D1 to Dx output toactuator(s) used to apply forces to the components, e.g., on arm linksof the arm 302, to link members and/or grip members of the control inputdevice 304, etc. In some examples, control signals D1 to Dx can be usedto provide force feedback, gravity compensation, etc.

In some implementations, a non-controlling mode module 1760 may be usedto control a non-controlling mode of system 1700. In the non-controllingmode, movement in one or more degrees of freedom of user control device1702, or other manipulations of user control device 1702, has no effecton the movement of one or more components of controlled device 1704. Insome implementations, non-controlling mode can include one or more otheroperating modes of the control block 1710, e.g., a selection mode inwhich movement of a control input device of user control device 1702 inone or more of its degrees of freedom and/or selection of the controlswitches of the control input device can control selection of displayedoptions, e.g., in a graphical user interface displayed by display device1720 and/or other device. A viewing mode can allow movement of thecontrol input device to control a display provided from cameras, ormovement of cameras, that may not be included in the controlled device1704. Control signals C1 to Cx can be used by the non-controlling modemodule 1760 to control such elements (e.g., cursor, views, etc.) andcontrol signals D1 to Dx can be determined by the non-controlling modemodule to cause output of forces on the control input device during suchnon-controlling modes, e.g., to indicate to the user interactions orevents occurring during such modes.

Some implementations described herein can be implemented or assisted, atleast in part, by computer program instructions or code which can beexecuted on a computer. For example, the code can be implemented by oneor more digital processors (e.g., microprocessors or other processingcircuitry). Instructions can be stored on a computer program productincluding a non-transitory computer readable medium (e.g., storagemedium), where the computer readable medium can include a magnetic,optical, electromagnetic, or semiconductor storage medium includingsemiconductor or solid state memory, magnetic tape, a removable computerdiskette, a random access memory (RAM), a read-only memory (ROM), flashmemory, a rigid magnetic disk, an optical disk, a memory card, asolid-state memory drive, etc. The media may be or be included in aserver or other device connected to a network such as the Internet thatprovides for the downloading of data and executable instructions.Alternatively, implementations can be in hardware (logic gates, etc.),or in a combination of hardware and software. Example hardware can beprogrammable processors (e.g. Field-Programmable Gate Array (FPGA),Complex Programmable Logic Device), general purpose processors, graphicsprocessors, Application Specific Integrated Circuits (ASICs), and thelike.

The functional blocks, operations, features, methods, devices, andsystems described in the present disclosure may be integrated or dividedinto different combinations of systems, devices, and functional blocks.

Although the present implementations have been described in accordancewith the examples shown, there can be variations to the implementationsand those variations are within the spirit and scope of the presentdisclosure. Accordingly, many modifications may be made withoutdeparting from the spirit and scope of the appended claims.

What is claimed is:
 1. A counterbalance apparatus comprising: a spring;a tension element including a first end coupled to the spring and asecond end coupled to a mechanical ground; a base element coupled to aload; a configurable arm including a first portion and a second portion,the first portion of the configurable arm being rotatably coupled to thebase element, and the configurable arm being rotatable about a firstaxis; a first pulley rotatably coupled to the first portion of theconfigurable arm and rotatable about the first axis; and a second pulleyrotatably coupled to the second portion of the configurable arm, thesecond pulley being rotatable about a second axis and orbitable aboutthe first axis; wherein the tension element is at least partiallywrapped around the first pulley and is at least partially wrapped aroundthe second pulley; wherein the configurable arm is rotatablyconfigurable about the first axis at one of a first orientation and asecond orientation; and wherein the first orientation is associated witha center of gravity of the load located on a first side of thecounterbalance apparatus, and the second orientation is associated withthe center of gravity of the load located on a second side of thecounterbalance apparatus opposite to the first side.
 2. Thecounterbalance apparatus of claim 1, wherein: a third axis intersectsthe first axis, the second axis, and a center of gravity of the load. 3.The counterbalance apparatus of claim 1, wherein: the configurable armincludes a length defined by the first portion and the second portion;and the length is aligned with a third axis that intersects the firstaxis, the second axis, and the center of gravity of the load.
 4. Thecounterbalance apparatus of claim 1, wherein: the counterbalanceapparatus further includes a first stop member associated with the firstorientation of the configurable arm and a second stop member associatedwith the second orientation of the configurable arm; the first stopmember is located in a path of clockwise rotation of the configurablearm about the first axis; and the second stop member is located in apath of counterclockwise rotation of the configurable arm about thefirst axis.
 5. The counterbalance apparatus of claim 1, wherein: thefirst portion of the configurable arm is rotatably coupled to the baseelement by a shaft.
 6. The counterbalance apparatus of claim 1, wherein:the counterbalance apparatus further includes a rotatable shaft having alength and an axis of rotation about the length; the base element is ajoint gear rigidly coupled to the rotatable shaft; the configurable armis rotatably coupled to the rotatable shaft; and the second pulley iscoupled to the second portion of the configurable arm such that thesecond axis of the second pulley is at a location offset from the axisof rotation of the rotatable shaft.
 7. The counterbalance apparatus ofclaim 1, wherein: the base element includes a first slot and a secondslot; and the configurable arm engages with the first slot at the firstorientation of the configurable arm and engages with the second slot atthe second orientation of the configurable arm.
 8. The counterbalanceapparatus of claim 7, wherein: the configurable arm includes a plugportion; the plug portion includes first tapered sides; the first slotof the base element includes one or more second tapered sides; thesecond slot of the base element includes one or more second taperedsides; and the first tapered sides of the plug portion are engageablewith the one or more second tapered sides of the first slot and thesecond slot of the base element.
 9. The counterbalance apparatus ofclaim 1, wherein: the second portion of the configurable arm includes afirst aperture, and the first aperture includes a threaded portion and aclearance portion; the base element includes a second aperture; and thecounterbalance apparatus further includes a bolt extending through thefirst pulley, through the first aperture of the configurable arm, andinto the second aperture of the base element.
 10. The counterbalanceapparatus of claim 1, wherein: the first orientation of the configurablearm counterbalances the center of gravity of the load located on thefirst side of the counterbalance apparatus; and the second orientationof the configurable arm counterbalances the center of gravity of theload located on the second side of the counterbalance apparatus.
 11. Thecounterbalance apparatus of claim 1, wherein: the tension element is acable.
 12. The counterbalance apparatus of claim 1, wherein: thecounterbalance apparatus further comprises a third pulley rotatablycoupled to the mechanical ground; and the tension element is wrapped atleast partially around the third pulley prior to being wrapped aroundthe second pulley in a path of the first end to the second end of thetension element.
 13. The counterbalance apparatus of claim 12, wherein:the counterbalance apparatus further includes a fourth pulley rotatablycoupled to the mechanical ground; and the tension element is wrapped atleast partially around the fourth pulley prior to being wrapped aroundthe third pulley in the path of the first end to the second end of thetension element.
 14. The counterbalance apparatus of claim 1, wherein:the counterbalance apparatus further includes a curved element and athird pulley; the curved element is coupled to the mechanical ground andincludes a curved surface; the third pulley is rotatably coupled to thecurved element and is rotatable about a third axis of rotation that isnonparallel to the first axis and the second axis; in a path from thefirst end to the second end of the tension element, the tension elementis wrapped at least partially around the third pulley prior to beingwrapped around the second pulley, and the tension element is at leastpartially wrapped around the curved element prior to being coupled tothe mechanical ground at the second end of the tension element; andalong the path from the first end to the second end of the tensionelement, the tension element exits contact with the third pulley andenters contact with the curved surface of the curved element at pointslocated within a plane that includes the first pulley and the secondpulley.
 15. The counterbalance apparatus of claim 14, wherein: the planeis orthogonal to the first axis and the second axis; and the third axisof rotation is at a non-orthogonal angle with reference to the plane.16. The counterbalance apparatus of claim 14, wherein: the curvedelement is rigidly coupled to the mechanical ground, is centered on thethird axis, and is located between the third pulley and the mechanicalground; the third pulley has a radius; and the curved surface of thecurved element has a radius equal to the radius of the third pulley. 17.The counterbalance apparatus of claim 14, wherein: the counterbalanceapparatus further includes a fourth pulley rotatably coupled to themechanical ground and rotatable about a fourth axis; the tension elementis wrapped at least partially around the fourth pulley prior to beingwrapped around the third pulley in the path from the first end to thesecond end of the tension element; and the fourth axis is nonparallel tothe first axis, the second axis, and the third axis.
 18. Thecounterbalance apparatus of claim 1, wherein: the first portion of theconfigurable arm includes an edge and a slot in the edge; and the slotis configured to receive a separation tool to slide or pry theconfigurable arm away from the base element.
 19. The counterbalanceapparatus of claim 1, wherein: the load includes a mechanical memberrigidly coupled to the base element; and the mechanical member isrotatable about the first axis.
 20. The counterbalance apparatus ofclaim 1, wherein: the counterbalance apparatus is included in acomponent of a teleoperated surgical system.